I have no issue with the art style. Not being able to remove districts (at a cost) is somewhat annoying, but it comes up rarely enough that I don't see it as an especially big deal either way. Builders, on the other hand, I'm not a fan of at all. They're probably the innovation of Civ VI that I dislike the most. Units with a finite number of charges that take effect instantaneously just don't fit with the rest of the game in my opinion. (The fact that missionaries work the same way also really annoys me.) Unfortunately, it seems very likely that they're here to stay, and modding them into a unit that makes more sense in the context of the game would be pretty difficult in my estimation.