hey dude great ideas but i just wanted to add some things i think would be neat to that.
1st i want a terrain editor in forge where you can make hills, mountains, valleys, rivers that kind of stuff
2nd i think it would be so cool to have useable boats as vehicles in forge and maybe even campaign
3rd which has been said before is larger air vehicles or human flying vehicles
4th also and maybe most of all i want firefight to come back with the ability to use custom maps
these are my top recommendations but with a game like halo they really cant go wrong