Call my cynical, but I don't feel sorry for those complaining about Iran getting nuclear weapons, especially Israel and the US governments. As bad as this regime is, what gives us the right to pick and choose which countries have it? To me, this is only part of the bigger issue of nuclear weapons in general. It's either you are for nuclear weapons, or you are not, you can't pick and chose.
If this whole thing is all because Iran is an Islamic regime, why have we not said the same thing with Pakistan? They have nuclear weapons, and it's controlled by Islamic fundamentalists, so why aren't they using it? I'm sorry, I'm not buying that bombing Iran is because of nuclear weapons. I feel they want to overthrow this regime. But again, who do they think is going to replace them? We saw what happened with Libya. I don't think the US has learned how to deal with the power vacuum that comes with overthrowing a government.
But ultimately, it shouldn't be the US or Israel deciding what Iran should be. Ultimately the question is, what do the Iranian people want? Are they ready for a parliamentary/democratic government? This is the problem with overthrowing a regime. They probably don't know how to do it (look up how the Arab Spring went where the governments ended up being worse). Let's not forget, there are religious zealot groups. How do we know that an even more Islamic fundamentalist group that is worse than the current regime isn't going to take their place? This is going to make Iran far less willing to negotiate because they see the US as nothing more than a dealbreaker who won't keep their end of the bargain.