I am aware there are ways to increase the current room limit. Heck, even without considering modding, I can save edit to give me more rooms simply by giving me a higher number on room's upgrade level than what's normally allowed.
That being said, I still think a much higher upgrade limit is better as a vanilla inbuild system even if performance is a concern. Because people with a weaker computer would realize not to upgrade it too many times, or keep a smaller pop once they hit a performance threshold, but it allows people with more powerful hardware to keep more characters.