I would give the VS series another chance if UMvC3 had some more modes in it. As it stands, I don’t feel like going balls to the wall with a game that’s too different when I’m trying my best to hone SF skills.
Shit, even Street Fighter itself is a lot of variety. Playing 4 and then going to 3S totally throws me off for at least an hour until I can get my mind right again.
The fighting games I am playing currently are:
SFIII3S, SFA3, KOF XIII, KOF 98, KOF 96, Fatal Fury (yes, the VERY first one), SSFIVAE, TTT, and Skull Girls.
I play the games I like and have at home. So at the moment, AE2012, UMvC3, KoFXIII and MK9. SCV would be added but I don’t have that yet. Had nobody I want to play until someone introduced me to Hilde at their place and her alternate costume with the musketeer/pimp hat.
I’d play SFxT but I don’t have it and I honestly feel my own personal hype for the game dying the less I play it.
If you genuinely enjoy playing the games, then no, there is no limit. If you want to grind and become absurdly good at them, you need to grind them one at a time.
As others have said, 2~3 are the suggested max. Personally, I think it’s nice to know how to play 1 game from different genres (Air dashers, 3d, traditional [SF], etc.).
For me, I main BBCS:EX and want to learn Tekken and SF. I feel that if you can become competent in a few genres, then you can play even more casually.
Because I main BB, I like playing around with P4U and GG when I go to arcades.