We can already watch game film on any game we want along with the game logs. This might be a lil overkill.
I can see where peeps might use it to look for exploits. It might also take a lil bit of the mystery out of game planning. Which is pretty fun in itself.
It would be nice if there were some sort of scrimmage ability to allow you to fine tune your gameplan and playbook, or to test adjustments without costing a game, but I'm not sure how fair that is, and as setherick notes, it would be a tremendous performance issue.
