The world of nations waited too long because they did not know what was the best thing to do. It puts Israel's very survival in the hands of Muslim extremists dedicated to the destruction of Israel.
Will Iran preemptively use the bomb? I think they will because they have been waiting for this very moment for decades and they will not want to lose the opportunity to destroy Israel.
You can't intimidate people that want to die. You have nothing left to threaten them with. The sooner they start this war, the sooner they destroy Israel, and the sooner they meet Allah in heaven from Israel's counter-attack. It's win-win for Muslim extremists. It's lose-lose for the citizens of Israel.
source: http://www.ynetnews.com/articles/0,7340,L-4078778,00.html