EA Sports is the best videogame company in the world and they even have a hard time making just a simple boxing game like Fight Night.
Imagine how hard it is to make a decent MMA game. Not just boxing, but kicks, takedowns, submission, GnP, etc. So many unpredictable variables in MMA that you can't put into a video game. for example Shogun freak injury or Chuck Liddell eye pokes.
hate to say it but there will never be a good MMA game.