I know I am restating some stuff I just want to add to the list:
- Doors that you can open with a switch (like in campaign)
- Vehicle Customization
- Spawn Dead Bodies, Blood Stains, Crashed Vehicles, ect.
- "Glue Tool"
- Play as Brute (People have been asking about it since Halo 2, I don't care that much but it would satisfy a lot of people)
- Forge trees, rocks, water, land formations
- A boat, UNSC Shark or something. A turret on the back, I think it would be cool.
- Civilian Vehicles
- Halo Wars Vehicles
- Spawn Bases, like real UNSC bases. (have bunkers, armory, stuff like that)
- Edit the length, width, and depth of objects (Length of a bridge for example)
- Spawn AI or forge firefight
- Snap to other objects to quicken the process of lining things up
- Bring back the dogfight like the level in reach, a lot of good custom could be created with that.
- "Copy Tool" If you make a blue team base, copy it, make it red and use that for red team so you don't have to build it again
- Pelicans, Phantoms, Frigates, corvettes, super carriers. we want them 343
- A level that looks like a normal neighborhood that we can go in houses and have a war in the city, places we can relate to.
- Desert, Snow, Grassland, Jungles. A weather modifier so it can snow, rain, ect.
- Be able to change the color of walls and stuff, EVERYTHING WAS GRAY IN REACH! remakes of maps took a while to figure out because you couldn't recognize it and it all looked the same.
-Weapon racks that actually hold weapons (like the level crows nest in halo 3)
I think forge could be improved to the point were halo reach forge would look extremely outdated and having a great forge would make halo 4 just that much better