Islam has gone from syncretic to more "orthodox," while Hinduism has re-defined itself in a more rigorous manner to act as a counter-point to monotheistic spirituality.
Much of what I have stated above is drawn from my readings of Bengali Muslim culture, which in the 19th century came under the influence of reformers who purged "Hindu" influences from conventional practice . Of course, this resulted in a secular Bengali backlash, and to this day the average Bangladeshi has a schizophrenic struggle over which is more important, their mother tongue, or their religion. It is often noted that even Muslims of exogenous non-Indian origin came under the influence of Hindu concepts, so it should be no surprise that indigenous converts imported some of their old paradigms into their new faith. Caste for instance continues among Muslims in a less formal fashion-but real nonetheless. My paternal grandmother's family continues to have Brahman tendencies in the way they carry themselves, which they are rather unaware of, but which are a source of amusement for my other relatives . My mother, whose family supposedly claims a Muslim lineage five centuries old, and who used to mildly mock her mother-in-law's "Hindu" manners once told me that I looked like my paternal grandfather because he died just as I was being conceived and "sometimes it is said that the souls of people are re-born." This she said with little irony and understanding of why this might be a rather Hindu way of looking at things.
These patterns are not found only among Indians, to give a non-Indian example, the Javanese continue to engage in pre-Islamic practices, maintaining a love of the Ramayana, the elites having a tendency toward philosophical monism, and continuing the pagan Javanese practice of slametan, offerings given to spirits during festive occasions . But, a subset of Javanese society reject these as non-Islamic accretions, and they are termed the santri (see this article for more details on Javanese Islam) . Traditionally the santri have been city-dwellers, merchants and students who study the Koran and the Hadiths, are in contact with the international Islamic community, and generally literate and "progressive" in their outlook. The other group, abangan, are the villagers who have formed the majority of Java's population for most of its history . The modern trend-line seems clear, as Javanese become urbanized and literate, abangan ways are ceding ground to santri ways. The abangan who refuse to practice the santri faith are now often converting ot Christianity or Hinduism, as those religions might be more congenial to their practices than their nominal natal faith! (this was especially true after 1965 when all Indonesians had to declare as part of one of the accepted religions, Islam, Hinduism, Catholicism, Protestantism or Buddhism)
India is further along this path than Indonesia, the abangan are a majority of Java's Muslims, but orthodox Islam is probably dominant in India, especially among the classes that count socially and culturally . I have given myriad reasons above why orthodox Islam and Hinduism have difficulties coexisting without enmity. Certainly, where Hindus have been a minority, in Pakistan and Bangladesh, they have been marginalized and sometimes driven out (I mean post-partition). The percentage of Hindus in both Bangladesh and Pakistan have dropped since independence, in the latter to almost neglible levels. In contrast, in India there has been stable or even perhaps modest increase in the number of Muslims. I do not believe this is because India is such an exceedingly tolerant state, but Hindu culture has a long tradition of giving a place to minorities, so long as they accept certain Hindu premises.
In the past, the premises of Indian culture did not need explication, and were left implicit. Hindustan imposed its own rules almost as a force of nature. Today the situation is different as India is a mish-mash of medieval and post-Industrial, globe-trotting elite and Bollywood celebrities inhabiting the same country which has the greatest number of people living in abject poverty in the world. Hindutva is I believe an attempt to respond to this changing world . They create anachronistic conceptions of the past, a Hindu Golden Age, Muslim evil-doers, and take the final steps toward religio-cultural lunacy by promoting pseudo-science and pseudo-history, not to mention making apologia for the slaughter of innocents that would make Wahabbis proud. As stated above, Hinduism is a broad and expansive faith in terms of dogma, or lack thereof, even if its ethnic and geographic horizons have tended to remain narrow, so it is interesting that Hindu fundamentalists should resort to the same sort of stand against the modern world that has bedeviled fundamentalists of the monotheistic stripe. Just as radical feminism can often become a warped reflection of misogyny, so radical Hindu fundamentalism is a mirror image of Islamism. There is a fair amount of evidence that twins raised apart tend to share similar levels of religiosity, if not the same religion, so Hindutva and Islamism are most likely drawing upon the same sort of personalities though toward putatively contrasting goals.
I believe that man uses religion to serve his own ends-so just as Islamism ends up serving self-aggrandizing autocrats, so Hindutva does little for the average Hindu, rather, it is a tool of the upper caste elite who wish to create the illusion of Hindu unity to mask the reality that the majority of Indians have always been under the rule of others, whether the lords are Muslim, British or upper caste. The resentment of the lower castes combined with the appeal of an egalitarian missionary faith is a recipe for religious instability, and so Hindutva arises to foment hatred against Muslims and make the down-trodden feel that someone else is the Other. Muslim contempt for Hindu culture, the idea that Islam is the most perfect religion and that the whole world will one day submit to Allah of course induces suspicion in others. But the very structure of the Hindu religio-cultural system makes it vulnerable to destabilization-and upper caste-I mean Hindu, apologia for caste as a buffer against the brutal competition of the Western world sounds as sincere as Islamist pleas that the sequestering of women into private life "frees them" from the worries of molestation and disrespect.
Stasis is not a characteristic of our world anymore, ancient Egypt lasted for 2,500 years as a continuous civilization, now republics are born and die in centuries. Liberal Episcopal bishop John Spong has written a book titled Why Christianity Must Change or Die. I believe that a part of that message is applicable to Western Islam, for Muslims must change their attitude toward living under non-Muslim rule. As one Muslim has stated, the believers must look to the Abyssinian model, where Muslims lived under non-Muslim rule without attempting to change the society. Unfortunately the "Abyssinian Model" is a bit too rosy, seeing as how eventually the Ethiopian state became embroiled in religious wars against Muslim states that began to envelope it. Pluralism is a fact of life that Muslims must get used to. Muslims on the borderlands have always had to improvise their practice and the religion has changed to accomdiate local traditions, is it any surprise that wine-drinking Bektishis flourished in religiously mixed areas (or that the liberal Hanafi tradition is found in South Asia and greater Turkestan?), or that in Sumatra the Muslims accepted the concept of queens among the matrilineal Minangkabau as the price for conversion? But in places like the United States, Europe or India, there is no great prospect of wholesale social conversion. Perhaps some Muslims see a precedent in Indonesia, where small enclaves of Muslim merchants and later the emirates that drew upon their industry and commerce rose up into Muslim thalocrassies after the fall of Hindu Majapahit, but this is not 14th century Java. In the past the elite could change beliefs and transfer allegiances while the peasantry by and large remained untouched in practice even if they worshiped different gods on parchment, but in today's mass society such social mutations are not feaseable . Pluralism in Christendom (post-Christendom?), what I term the "gelding of Christianity," took hundreds of years, several Reformations and the Enlightenment, but it shows that the God of Abraham is amenable to taming, but that the task is arduous and prone with difficulties. There are Muslim scholars who are pushing new ideas, that "the message" must be seen in the context of the times, that the prophets mentioned in the Koran need not be the only ones, that all peoples received the word of God. Unfortunately, when I read pleas for religious pluralism from a Muslim perspective, the voices arguing for acceptance of monotheistic religions are clarion clear and buttressed by many strands of Muslim tradition. Those who argue for expanding the circle of reciprocity to Hindus, Buddhists or pagans tend to be vague and less eloquent, and though Muslims in the past like the son of Shah Jahan Dara Shikoh have attempted it, that tradition seems not to have developed to nearly the same extent as the elaborations of reproachment and coexistence with Peoples of the Book. I think this is partially a reflection that the conception of a Creator God, the God of Abraham, the God of Isaac, the God of Jacob, who made a covenant with his Chosen People, whether that be Jew, Christian or Muslim, and the underlying theological foundations, make the task of reconciliation and dialogue a far easier task. Nevertheless, the mind of man is genius, even the most strident of fundamentalists are nimble in their interpretations of inconvenient facts, and I pray that the Muslim-Hindu chasm can be bridged with an application of reason and pious sincerity.
In the context of India I believe Hindus also need to change. Hindutva is a last gasp of the old order, the segmented structure of old India may still predominate, but it will be the background for the rise of a new social system if our modern technological civilization does not collapse. There would be far less threat from Muslim or Christian missions if the oppression of the caste system did not act as a driving force toward the abandonment of Hinduism . If Islam needs to transform its outlook to accomdiate pluralism in a world of many gods, Hinduism needs to accept into its fold fully those who it lays claim to, with dominion comes responsibility, the Hindu elite must earn their status now before the modernizing masses of Indians realize their spiritual bondage . As long as upper caste Hindus simultaneously treat lower caste folk with less dignity than animals but demand that they not convert to other religions to escape their spiritual, if not their corporeal, bondage, there will be religious tension in India. If Muslims are to re-open the ijtihad and embrace a world of religious pluralism among equals, Hindus must truly smash the idol of varna and the "wisdom" of Manu.
Hindus and Muslims need to shed the ghosts of the past, a memory of history that is in any case filtered by their own modern viewpoints, and proceed into the future untainted by ancient resentments ascribed to ages past but emergent only out of the past few generations. India does not have just a Muslim problem or a Hindu problem, both faiths need to change, need to adapt, and need to shift toward values more in keeping with this age. Playing the blame game only feeds the cycle of communal violence and resentment. Just as keeping your personal house in order facilitates familial harmony and communal amity, Hindus and Muslims of a moderate and tolerant disposition need to focus on their own co-religionists and make clear what is acceptable and what is not. The Hindu-Muslim problem is greater than the sum of its parts, the discordance emerges out of the interaction between the two faiths, but resolving the issues at stake will not only result in peaceful relations between the communities, but also further the individual well being of Hindus and Muslims. In an ideal world governed by Rawlsian principles we exist as idealized rational thinkers seeing little beyond our veil of ignorance, but that is only a thought experiment. Flesh and blood humans beings are born with history remembered through the lens of our community. Just as on the individual level is often difficult to take responsibility for short-comings, it seems clear that Hindus and Muslims often want to pass the buck and pretend that the structural deficiencies in their relationship are one-sided. Muslims need to be honest about their religion's attitude toward the un-believer, for their past tolerance has only been just that, tolerance rather than acceptance as equals. Hindu leaders must own up to the fact that the growth of Islam is not simply due to the perfidy or virtues of that faith, but rather impelled by the shortcomings of their own belief system, which like so many religions has become a means to perpetuate the unequal social structures that emerge out of circumstances of birth rather than merit. Just as human beings are by nature flawed, their religions will always fall short of their divine self conception, but it is also human to strive for perfection even if attainment remains an ever-elusive dream. Unitarian-Universalists have a phrase, "Sometimes the question is the answer," if Muslims and Hindus begin to ask "What did I do wrong? What are the problems with my religions tradition?", many of the difficulties and disputes will become far more tractable as the grounds for civil discourse have been set. To change long entrenched traditions and mind-sets is far easier said than done, but even if the attempt might be in vain, Indians need to make the effort, for the sake of the world, so that they may be a light unto the nations.
-- Razib Khan
 Even today my Salafi (Wahabbi) uncle lectures most of my relatives on "proper" conduct as a Muslim, telling them in plain terms that the more relaxed Hanafi tradition of South Asian Islam is deviant from the primitive and primal faith. He even berates my relatives on exactly how to hold your hands when you are praying.
 Generally it has to do with carry-over of hang-ups with ritual purity.
 More "traditionalist" Muslim groups like the Nahdlatul Ulema of former Indonesian PM Gus Dur have a strong base in East Java partially because they have established a modus vivendi with non-Muslim practices. "Modernist" santri Muslims of the Muhammadiyah movement like Amien Rais are more centered in West Java and especially in coastal cities like Jakarta. Of course, I use quotes around traditionalist and modernist, because it is the latter that tends to be less tolerant of other faiths and steeped in a more austere form of Islam.
 One last group, the priyari, is to my knowledge numerically insignificant at this point. They are the noble class who expounded their own synthesis between Islam and Javanese mysticism.
 What about the secular Muslim families that produce the likes of Fareed Zakaria and Salman Rushdie? I believe they are outside the Muslim, let alone Indian, mainstream, part of a transnational elite that is unmoored, intellectually mobile and adaptable in a way that is unfamiliar to the typical rural Indian or city slum dweller. The petite bourgeois are the natural leaders of this latter group, as the BJP also draws from this group and simultaneously claims to represent the mass of poor Hindus (though other parties get most of that group's votes).
 Interestingly, the political leaders of post-partition India and Pakistan were atypical, brown Englishmen in many ways. Nehru's concern about his daughter's marriage to Feroze Gandhi was not that he was a Parsi, but that he was middle class, while Jinnah, a lover of scotch and pig (I'm a better Muslim than Jinnah, pig is foul and I don't drink much hard liquor!), married a Parsi as well, as did his daughter (though he rejected her for that act).
 Muslims and Christians often speak of the deviltry of the Hindu masses with disgust, but I speak of the abominable concept that one is born with grace and virtue or one is born to filth and degradation.
 In Europe cuius regio, eius religio was abandoned in Prussia when the Elector of Brandenburg became a Calvinist, while his subjects remained Lutheran, showing the growing power of mass religion in the face of the fiat of the ruler. Later, Frederick the Great promoted freethought and rejected traditional Christianity, though his subjects remained orthodox Christians.
 A compromise might be the strategy of the Neo-Buddhists, who remain within the general scope of the Indian tradition, while rejecting caste.