I’ve seen several discussions on players circumventing the war support mechanics by simply ransacking the city centers they capture, thus removing the city center outright. I personally like this workaround, but I don’t like the fact that it is in fact a work around. I feel that if you’re going to be able to ransack territory you take, you should be getting some form of penalty, similar to how Endless Space 2 penalized your stability if you destroyed a system outright. I’m curious to know if self ransacking was intended or if it was a bug, but I personally think it’d be fun to leave the mechanic in as a feature with some penalties. For instance, stability penalties, or instead of letting you destroy the city in one ransack, force the player to ransack every district around the city center as well—after all, a city isn’t looted to oblivion in a single day.

I disagree with the method, but you must absolutely be able to "demote" cities. All these independents sprout up as cities and you don't want to keep them when you win (also you can't leave them alone because they fight you and spawn rebels). So there needs to be a way to get rid of own cities (cities you have captured). They shouldn't call it ransacking, but something needs to be there.

Also, in early game, if you let the independents go, they can have like 10 districts so quickly. I don't want all those districts either - it's like they're more advanced than me. If I was the ruler (and I am), I wouldn't allow that city to outshine my capital. So I spend several turns to ransack every tile.

You already get the penalty of losing all the population, districts and infrastructure that city has. Any additional penalties might go overboard. I would like a more elegant solution like in Endless Space 2 - you have an option/button in the build queue to abandon the city but it will not do it immediately - it should start depopulating the city one army at a time using the cheapest unit possible (probably the militia units should be best option or even create a specific refugee unit). You will need to both pay their wages/support and then transport then somewhere. Thus abandoning a city won't be so fast and you will still pay a small penalty in gold for the support.

I don't think you lose the population when ransacking, I ransacked cities and built outposts on their territories and they kept the population that the city had.