They would have to have a complete change in government, not just dictator, because the religious leaders, mullahs, or clerics are in charge and have been since 1978 or 1979 when they overthrew the Shah. It is not like Iraq, where when Saddam was out of power, that government was gone.
I don't know how power is distributed between the current guy, whose name I can neither pronounce or spell; and the clerics. But as long as they are in power, even if Mr. A. went away, by assassination, being overthrown or just stepped down, little will change in Iran.
But we saw in the late 70's, when that generation of young people wanted change from the Shah's regime, they can overthrow a government. That generation is now in their 50's or 60's, but the younger generation today might want something different than religious tyranny and a power crazy dictator.