I was thinking of having bigger maps for more fun and mayhem. that also take awhile to get to the other side on foot but faster with the help of a ride making the rides more useful in game. Maybe the map should have hip deep water that you can walk through just for fun.
Also maybe some more flying vehicles like the Hornet and Hawk from halo wars for the UNSC rather then just the Banshee because I missed the Hornet from Halo 3 and maybe add more land vehicles like the Elephant, Grizzly, Cobra, and more from halo wars and maybe some new UNSC vehicles that can shoot on their own kinda like the Ghost.
Since the UNSC are getting more vehicles maybe give the covenant more vehicles from past games to make it even and new unseen ones too.
So if anything think that this maybe a good Idea let me know please and not to harsh no’s and if you have any vehicles that maybe good in the halo 4 game or new halo. 
Driveable elehpants/mammoths like the ones in Halo 3 on Sandtrap would be nice. Sure, they weren’t all that useful in combat but they were fun to play with.
They were fun but be cool to drive one your self maybe a automated turret behind you so you have a less chance of dieing from behind when driving an elephant or just go with a mammoth. maybe just go with a smaller version of the mammoth itself that you can drive that has turrets on it that can be mounted and some passanger seats on the sides and front that people can hop in and shoot from like the passanger side of the warthog.
Also I had more Idea’s come to me while thinking about this and I thought it would be cool where you can make your own vehicles and weapons and armor stuff like abilities and armor variations. On the maps have the blown up vehicles not disappear so that you can use them as cover like you and someone else can go up to a blown up warthog and tip it on its side and use it as cover, the other thing is to have the visor of your helmet crack and break if its been melee’d to much and if you hit the ground face first a lot. once that happens you have to rely on your senses rather then seeing how much grenades left and ammo and the shell casings from previous shots stay on the ground.
Also feel free to add your own Idea’s please.