I've been saying this forever. If they slightly modify the fight night analog system, it can make an mma game much more effective. Right stick for punches (jab, hook, uppercut) a shoulder modifier for kicks... say L1, or whatever that translates to in Xbox talk (jab motion = leg kick, hook motion = middle kick, uppercut motion = high kick). That leaves 3 shoulder buttons open, R1 for blocking (bottom left/right for leg kicks, left/right for body kicks, top left/right for punches/high kicks). This sort of leaves a problem with how to throw body punches, but this is just my quick idea on the game, so I'm sure people who do this for a living could figure it out.
So we still have 2 shoulder buttons left. L2 for a left single leg, R2 for a right single leg, both for a clinch, both and forward for a double leg. In the clinch, right stick for punches/elbows, and L1 and right stick for knees. On the ground, the right stick can be used for punches, and L1 and the right stick can be used for elbows. This leaves three shoulders again... R1 for blocking, L2 for passing to the left, and R2 for passing to the right. This still leaves all the face buttons open for subs. For passing and subs (and takedowns), there needs to be some sort of struggle to accomplish whatever you're trying to pull off. Whether that means moving the left stick in a motion to simulate the movement you'd actually have to make to pull a move off, or a sequence of buttons (I couldn't really determine which would be more effective without actual testing).
This is all just actual gameplay stuff, obviously there has to be an in-depth set of attributes to determine strength of strikes, endurance, ground control, subs, sub defence, etc (I know I wasn't even close to naming everything, that wasn't the point, just giving examples). And the game modes and roster are important too, but I feel the most important part of this game and its success will be gameplay, so that's been the biggest part of my thought process about the game.
Just based on my brief 5 minute analysis, they should be able to pull off a much improved game from the previous UFC attempts. And if they can't... for shame, and I should be hired to be the project manager for the next game.