I play MK9 occasionally, not all the time, so I don't think it will effect it much. If I'm wanting to play MK, I'll play MK. If I want DC, I'll play Injustice. Marvel, UMvC3. Obviously once it comes out, I'll be playing it a bunch though. I just don't have the attention span to play the same game for years like I used to. Now I'm lucky to get a month straight out of a game before I start playing other stuff. I always go back and play them over time though.
I'm not a tournament player though, so I'm guessing I'm not the intended audience for the question. lol