Okay, a few points:
1. Hezbollah is on the State Department's list of terrorist groups:
http://www.state.gov/j/ct/rls/other/des/123085.htm Iran is a state sponsor of terrorism, including but not limited to the Marine barracks bombing in 1983, the AMIA and embassy bombings in Argentina in the early 90s, a plane hijacking in the 80s, etc. Just this year there were bombings in India, Bulgaria, and an attempted attack in Cyprus. That's even ignoring all of the help/training given by the Revolutionary Guard to insurgents in Iraq. Even ignoring Hamas (which is admittedly less strong of a connection that Hezbollah), there's ample reason to label them a rogue state. (The whole thing with nukes is only part of the picture - agreed that they might not yet be in violation of the NPT (they were earlier due to undisclosed enrichment facilities and weapons design work), but they might be - there's some evidence they're working on weapon design based on some implosion test work going on at Parchin et al. Even so, the record of repeated lying, obfuscation, etc. tied in with clear sponsorship of terrorism against Western targets and a sketchy human rights/democratic record... I think that's pretty much the definition of a rogue state.
2. I personally agree with you that it's
likely Iran won't use its nukes offensively. But I don't think it's ruled out at all, and the concerns of proliferation are also pretty significant (I'm not as sanguine about Iran's connections with terrorist groups). I think that given the weight of rhetoric and Iran's continued intransigence to international pressure it's very hard for a country like Israel to rely on a gut feeling that once Iran acquires nuclear weapons capability they'll act rationally. I think that in such a situation preemption/prevention is justified. If one was doing it just because of some concern over Iranian influence, I'd agree with you, but I don't think that's the motivation. The motivation is existential, even if you, from the comfort of the US, think it's unlikely to be a threat.
I think the case for intervening in Iran is much stronger than the case was in Iraq. Iran is more ideological, has stronger direct ties in funding and direction to global terrorism, and has an active and large (and largely undisputed) nuclear weapons program. I personally think that regime change would be challenging and a bad idea (and probably illegal outside of UNSC approval), but a limited strike to take out their nuclear sites seems reasonable.