Listen son. If you are trying to get good at a fighter and by good I mean actually compete in tournaments and win, you are not going to play the ai and get better.
For example. In Marvel vs Capcom 2, when you play Magneto, is the cpu gonna do rom inifintes and resets and use it's assists properly? No. The computer isn't going to do anything but spam random stuff like a noob because it is terrible.
In CVS2, when you play Bison on A groove, is he going to paint the fence? No, he's going to do some random CC that does nothing and you are going to think you know how to fight Bison and then get wrecked if you ever have to play someone who actually knows how to use bison.
The point is that important things like mind games, mix ups, traps, and pretty much all the important stuff you need to know in high level play you won't learn from the ai. The only thing you get from the ai is the most basic noob level of play.
If you actually want to learn about fighters, go to www.shoryuken.com and read the forums.