This was partially brought up in the HaloGAF thread and I thought I would expand it from just focusing on Reach to opening it up to the entire franchise. We're talking features such as maybe theater to even certain maps and weapons.
There are some that are very dear to me and I'm just going to name a few to get it started.
From Halo 3, I would love to see the return of theater mode that allows more than 1 player to view a film. In Halo 3 you could have up to 4 people watching a film together in theater mode. In Halo Reach, for whatever reasons, that was brought down to 1. Obviously there were some technical issues. I used to love getting in a party with my team and breaking down film together. You can't really do that in Halo Reach.
From Halo Reach, I would love to see the return of the Active Roster. Active Roster is basically UI feature that shows your friends who are playing Halo Reach. It's fast, it's smooth and with just a few button presses you can get detailed information on the gametype they're playing, the score, the time remaining along with the people they're playing with. You can also invite people from there very quickly and easily. Everyone knows just how clunky the Xbox Dashboard can be.
From Halo 2, I would love to see the return of Midship. It is by far my favorite multiplayer map from the Halo series. It works so perfectly for 8 players and just about every gametype works on it. Doesn't matter if you want to play Free For All, Oddball, Slayer, CTF or whatever. It just works and does so without a hitch. The map allows for unique jumps and ledges that add to its depth and really rewards creative players who excel in map movement.
So GAF, what elements of previous Halo games do you want to see in Halo 4?
There are some that are very dear to me and I'm just going to name a few to get it started.
From Halo 3, I would love to see the return of theater mode that allows more than 1 player to view a film. In Halo 3 you could have up to 4 people watching a film together in theater mode. In Halo Reach, for whatever reasons, that was brought down to 1. Obviously there were some technical issues. I used to love getting in a party with my team and breaking down film together. You can't really do that in Halo Reach.

From Halo Reach, I would love to see the return of the Active Roster. Active Roster is basically UI feature that shows your friends who are playing Halo Reach. It's fast, it's smooth and with just a few button presses you can get detailed information on the gametype they're playing, the score, the time remaining along with the people they're playing with. You can also invite people from there very quickly and easily. Everyone knows just how clunky the Xbox Dashboard can be.

Beta shot but it gives you the idea
From Halo 2, I would love to see the return of Midship. It is by far my favorite multiplayer map from the Halo series. It works so perfectly for 8 players and just about every gametype works on it. Doesn't matter if you want to play Free For All, Oddball, Slayer, CTF or whatever. It just works and does so without a hitch. The map allows for unique jumps and ledges that add to its depth and really rewards creative players who excel in map movement.

So GAF, what elements of previous Halo games do you want to see in Halo 4?