As an addendum to this thought I'd like to see players pushing (shoulder to shoulder, maybe a little arm too) for 50-50 balls where both players are running the same direction. In 2009, if one guy is dribbling and the defender can run even with him you'll see it, but not on 50-50 balls.
I don't know if there's a button you could map to this. I'd hope a player with higher strength or balance ratings wouldn't always win and there would be different variations.
Maybe things would play out differently depending on the scenario. Say a stronger player might win the ball *almost* every time if they can get their body a little inside the other player, a good amount of the time if they are even, and maybe would risk fouling more if they let the other player get inside of them. Possibly a much shorter player could beat a stronger defender for the ball due to lower center of gravity. It shouldn't always play out the same if you have the same two players going after the ball is what I'm saying.
This scenario doesn't happen all that often in the game, but it would still add to the realism. Give a slower player a chance to win the ball over a faster player so it's not just a foot race. After all, that's a tactic I use quite often in real life (yeah, I'm a slow center back) to great effectiveness.