Something I think should be stated, I think the Carnage Report needs attention.
Compared to the previous Halo games, Reach’s Carnage Report simplified the medals, etc., but left out a great many important and/or interesting tidbits that the other games in the series brought to the table. Now to get specific, the THREE MAIN ADDITIONS I would like to see return to the Carnage Report after a game, is:
1.) Shots fired (Halo 2) - It really determined who was putting in more work in terms of trying to get assists, lay down cover/suppressive fire to shield teammates or delay caps or objective pushes. Not to mention who’s actually challenging throughout the course of a match, if a player doesn’t get into a fight for… give or take, 14 seconds into a game, and avoids helping his teammates because he’s taking longer routes or avoiding hectic areas to bait teammates, the only way we have to figure that out currently, is Theater which is hella tedious.
2.) Shot accuracy (Halo 2) - I think this is an obvious addition, but this is obviously my personal opinion, I just think it’s important to know exactly who’s shots are hitting, who’s on fire and have legitimate proof if the host was as bad as some whiny teammates may actually be. 
3.) MVP of the match (Halo 3) - One of the coolest features I thought from the Halo 3 Carnage Report was the MVP. It calculated the overall best player statistically from both teams. And for casual gamers, I think this would instill a strong core philosophy of “I want to be the MVP of the match.” Now sure, this could be detrimental to the idea of the game, and cause more stat -Yoink!- in casual games, but at the same time, for competitive play, it would certainly give you some bragging rights, or at least boost your morale.
Another area I would like to address. We NEED separate customizable power up options for both Active Camo and OS. Not to mention, a real, working Over Shield. It’s ridiculously important to me, because as of late, over the course of Halo 3 and Halo:Reach, the powerups have lost a lot of their flare in my opinion, due to the complications and confusion that the Custom powerup brought to the table. I want my original powerups back and not in the form of some cheap armor ability either.
I would really like to see the “Freeze” or “Stun” feature of the Plasma weapons back in action as well, but due to how difficult it is to cultivate for Xbox Live, I may never see that, but it added a very unique dimension to the sandbox. Also, I wouldn’t mind seeing the return of the Mauler over the Shotgun or maybe some slick combination of the two. Obviously, as a CE player, I support static weapon and item timers as well.
On the subject of Theater also, I really want the ability to watch files with teammates in theater to review gameplays and easily explain positioning, etc. instead of having to synced up exact times with two separate players watching the same film in different lobbies, that’s just… elementary.
And lastly, before I end up writing a novel here, I want to add, that the announcer for the medals should only chime in on Killing Sprees and Multi-Kills. I could care less to hear something like “Revenge!” 600 times. 
All in all, I have hope for once in a Halo title. I just hope 343i really pays attention and plays their own game in a highly competitive mindset.

