I think they should include actual pileups when there's a fumble. More times than not, the players just stand around trying to pick the ball up like they always want to run back the fumble. Better hands for defensive players would be nice (even though the number of INTs I throw would go up). Put more people standing on the sidelines. In all past games, there's only been a handful of people standing on the sidelines, which isn't realistic.
The fumble thing could be annoying if you have a clear path... Unless they made it so they only piled up when it was actually a situation where you should...
Make the cornerbacks more likely tor try to grab the ball instead of batting it down, and make them worse at one on one coverage. You should be able to win that with an average wr some of the time.
Make it a little harder to block fg's and extra points.
And fix pass interference. If the WR won't run around the DB whose fault is that. The DB doesn't have to move... Make it so interference is called when the db runs into the player, not when the WR runs into a db just standing there.
Also, make it easier to control if you lead the pass or not... After you press A you should have some control about where the ball goes instead of the game automatically assuming you want to catch the WR on a full sprint. Gets annoying near the sidelines on what should be a ridiculously easy throw. Which reminds me, when a quarterback is under pressure, he should be able to hit a receiver who isn't running and is standing about 5 yards away. The QB should make any throw a 15 year old kid like me could....
And lastly, add some variety to commentary. Boost their IQ's, too. It may make it unrealistic, but still more enjoyable... I don't need to hear them kiss ND's @$$ in a videogame, too.