well its more nuanced than that. an ayatollah doesnt hand down the word of god, he is a really well respected mujtahid basically, which means that he interprets the rules laid down in the Qur'an and various other religious texts to provide spiritual guidance for the people of his time.
so overthrowing the ayatollahs would not so much be overthrowing the word of god as much as it would be just opening ijtihad (islamic exegesis) to the masses, and then basically there would be the equivilant of the reformation, except it would happen only within 12'r shiism. thered be those that stuck with the ayatollahs and then thered be a shitload of poor clerics without any higher education goin around preachin about whatever the hell they want pretty much. but all this unrest isnt about overthrowing the ayatollahs. hardly anyone in iran wants to bring down the islamic republic, they are all just tired of ahmadinejad basically
on the one hand though its difficult to estimate the relative level of piety of the iranian nation as a whole, but in general they are more religiously conservative (and traditional) than we are here in the united states, but they are prone to unpredictability when novel situations arise (as any multi-ethnic nation is certainly). but its hard to say that the problem in iran is that their religion and their state are closely tied together. the whole idea of the islamic republic is a pretty solid one, it just got quickly bastardized and authortarian heh
but yeah I personally wouldnt want to live in a theocracy lol
basically what I want to say is that the islamic republic was what the people needed in the 70s, they wanted a regime change, and at least originally, the new government that they ended up with represented their values and desires and fulfilled their hopes, but then shit just went back to not really being any different other than that the line of persian kings was finally broken for good. so its hard for me to bash the islamic republic, even though it seems so evil and terrible to people who arent as familiar with iran, because it perfectly suited what the people were after at the time, and who am I to judge that you know? What I do know is that the system is no longer working and something else needs to be tried, and in general there needs to be better and less corrupt leadership across the board