As I noted earlier this month, Mordechai Vanunu has been released from prison yesterday. Jonathan just changed my mind about Vanunu on the spot - I hadn't really given any thought to the fact that he was actually a traitor to his country. My personal sympathy has diminshed considerably from that perspective.
However, I do think that Israel needs to openly acknowledge its nuclear weapons. There may be some increased pressure to sign the NNPT, but other countries (notably India) have succesfully resisted the same pressures, with good rationale. There is zero ambiguity about Israel's possession of nukes, so the concept of "strategic ambiguity" is farcial now.
The benefit to Israel in acknowledging its nukes would be, IMHO, greater deterrence posture. Also, it would allow Israel to carry out the testing and maintenenace of that arsenal in the open, which improves the safety and reliability of those weapons (should, god forbid, they ever need to be used). Finally, with open acknowledgement of the nukes, Israel can pursue research into nuclear power, allowing technology transfer to flow freely in both directions from military to civil use. One great use for nuclear power in Israel is water desalinization, which could even create a water export industry for the region. There are economic and industrial benefits to an open program that can greatly benefit Israeli society as a whole.