I've been giving fifa a go for the past week and it isn't as bad as i initially though.
While I think pes 2013 was clearly the better football game, there's two things I really want them to change about the gameplay:
1. Pace and dribbling. In pes 2013, they made pace a bit too irrelevant. Sure, in fifa, having a top player with pace is almost like being on god mode, but pes made it tad too irrelevant. Even if a player is extremely quick, defenders seem to be able to keep up with him almost always. The acceleration isn't enough. Similarly with dribbling, you seem to have to try way too much to beat your man and unless you do something very "different" like tricks, the defender knows your next move too well. You should be able to beat your through simple but well executive changes of directions as well. They've tried to make it a challenge but maybe they need to dial it down a bit. But not go to the extent fifa goes where you can beat the defender for fun like all your skillful players are messi.
2. Opposition teams tend not to keep the ball well. They almost always attack in a direct manner and end up losing possession easily. Whereas in fifa the CPU is by default in barcelona mode, pes does the opposite and even barcelona will play the most direct pass possible every time leading to your team always dominating possession.
Obviously the changes in master league are the most important but that's been discussed plenty.