I think Israel needs to wait. If they act now, the government will tell the people they need to rally around Ahmadinnerjacket and be happy he was "elected," in order to fight off the evil Zionists. It will come out that 'allah' told the mullahs Ahmadinnerjacket was the correct choice.
If the Israelis keep a close eye on events (and watch for Iran to pull a Reichstag fire) and let them run their course, they can allow the Iranian people to undermine the regime. And, if the "moderate" comes out on top, maybe get him to stand down. If not, they are in no worse shape than they are now..... except the only way for Ahmadinnerjacket to come out on top is to brutalize the opposition, which the Israelis can use to their advantage later.