About Donkey Punch, here's the issue:
DK cannot use it in the air at all without having to worry about having that fall special. It wouldn't suddenly be broken if he didn't have it, he'd still have wind-down lag from the punch and he would still need to land again before chasing his opponent. Why give it a fall special? It cripples the move in the air. Also, here's some food for thought, DK's punch never had the fall special in Smash 64, it wasn't until Melee did they add it. Think of it as bringing something back to a character that didn't need a nerf to it in the first place.
Again, the wind-down the punch has is enough to slow DK down from abusing it as well as the fact that you wouldn't be likely to see a DK do this: Donkey Punch > Dair, not enough time, they'd be out of hitstun due to the punch's great strength. Rather, you'd see a DOnkey Punch END combos like it should in the air. Think of it as fixing the move that got a hard nerf from Melee which he didn't need.
That's all he would need and he would be perfect. I would love to not die from using a Donkey Punch offstage to finish a combo (my combo video gives a good example of why it's bad:
http://www.youtube.com/watch?v=PLU1G...e=channel_page). I get punished for using it in the air? Makes no sense especially since I'm supposed to get rewarded for landing it in the air in the first place. It contradicts the move in the air.
By the time you land, the opponent is out hitstun, is the bottom line.