Lets see...
1. Rumble Pit - Was my favorite thing to play as I didn't have to rely on team mates being good and thus I ranked the highest in it.
2. 1-50 ranking. Right now the only thing to compare for ranking is KD ratio, something I never cared about before in a halo game. With actual 1-50 ranks, I can be happy again by just going +2 or 3 kill a match, and not strive to sit back and get a 2 KD ratio. Especially when I get paired with a bad team, I just feel like sitting back so I don't ruin my ratio...
3. In Dominion, fix capturing. Many times I've completed capturing and then can't move, and as a result, I die from it. Also happens sometimes when cancelling a capture.
4. Spawns. Mostly They're alright, but I've had times were I've spawned directly in front of an enemy wraith as its shooting directly at me. That is crap.
5. Button Layout - I consider this an issue and it limits my mobility. I hate B to crouch and Left stick click to sprint. I want an option to have them reversed. Boxer does this but also changes melee. Why can't we just get an option to switch them? In my opinion, Left stick click to crouch made many jumps a lot easier.