You cannot have tiering and balance in a general MUGEN. It doesnt even come down to strength or comboability but the variety of system and tech. The reason the FGC does npt take MUGEN seriously is they see it as a game and not an engine. You are making that same critical mistake. To have balance you need to move to the fullgame environment. Otherwise there is no competitive merit to MUGEN at all. Even with those Ikemen sets, its just a compilation of random pots styled chars, most with different systems.

Well then its for fun yeah, no problem. But there is no competitive aspect. Also a blanket "balance roster" is hard to achieve. There are too many standards of what balance is from game to game

Where are you getting this tiering data from? Just watch mode?

Proper tiering has to do with specific matchups, so its impossible to get accurate or even consustent. I'm glad you arent doing based on watch mode, its a mistake I used to make.

Like many people here, I do think that trying to make any meta/tourney sense out of MUGEN is a fool's errand. But if you are so dead set on its completion, then good luck.