My only problem with your idea is that in ALL their rhetoric, the Ayatollahs refer to America as the Great Satan. They seldom if ever refer to any European nation.
If they can master multi-stage rocketry, the difference between hitting Paris or London and New York or Washington isn't as great as many might realize.
Indeed, we may have to deal with them all alone, but let me rephrase my point for you.
If Iran goes nuts in the short term, it is more likely to force the Europeans to get involved. If we massage the problem through the short term, then it becomes more and more a U.S. problem. That is hardly a benefit to us.
I'd be all for dealing with the problem now, but that doesn't appear politically possible. So should we delay (which adds to their capabilities) or should we allow the political dynamic to change? I'm advocating the latter.
There is sometimes benefit to providing more rope, when someone is in the process of hanging themselves.