This wouldn't be a very large change, but I'd suggest two things:

1) A slider to quickly move through the frames of annoyingly long replays that you're trying to edit.

2) Either a slider or a setting in the options which makes replays pass by faster. I can't figure out how to say this without it coming out wrong, but I want there to be an FPS slider. If I remember correctly, in the Wii version, you can choose the speeds at which replays go. This would make watching replays that are supposed to be realistic look much better when you speed them up. Also, recording would be easier as you would be able to record replays at decent speeds, instead of having to edit the footage the slow them down or speed them up.