In a nutshell: Good riddance.
With respect to timing, however, it was a complete mess. By executing Saddam so close to Eid al Adha, they played into his own desire for martyrdom status, and exacerbated the Shi'a-Sunni tensions already so raw in civil-war-torn Iraq.
For what it's worth, note that Saddam was hanged, so any attempt to link his execution to the act of zabihat is nonsense. This was an execution of a criminal, and anyone who tries to argue that the date of same is somehow an insult to Islam is giving Saddam a completely unwarranted religious validation. Had Saddam been beheaded, the analogy might have some grounding, but as it was, Saddam was hardly the first devil to die and won't be the last. That's the only lesson to take: Saddam was executed by his nation for crimes against his own people. That's another reason to celebrate on Eid al Adha.