Basically what the title says. I've had a few game overs recently because the Serene Doge angered the peasants, and then when the revolt spawns he can't raise his troops.
I don't mean to sound condescending or rude, but I think that your suggestion would make MRs way too OP, especially seeing as everyone has to deal with peasant rebellions from time to time, if you're the Serene Doge, you just need to manage your peasants better- if there's a risk of a revolt you can send your marshal to suppress revolts which lowers the likelihood of a revolt happening. If you managed to conquer a city away from your capital, you could raise mercenaries and move them to your capital via ship to suppress the revolt.
If you're a patrician under an AI Serene Doge, then I'd suggest trying to gain an external territory away from your liege's capital, e.g. a city or a county, that way the revolt shouldn't affect you too much.