Somethings I would like to add as well would be:
1. Hopefully they do approve forge on staying.
2. A pelican, make is slow like the one in Reach you can drive but don't make it invulnerable, but for the health I would say make it the same as a phantom. FYI takes about 4-5 well placed shots to destroy one.
3. Troop Warthog, it gives people another warthog to ride around in, it's a simple idea and could make it easier to support your team. Make it for players to ride in the back seats as well. This also makes a good quick response vehicle for CTF or Assault.
4. AA Gun, this would make great idea for base maps. Just for the fact that if someone so happens to be assaulting your base with banshees or whatever it would be great. Let it be player controlled that way it's not a cheap shot from an AI control as well as give it a health bar for about something equivalent to a pelican.
and last,
5. I would want the most simple things in forge, put vehicle skin colors. In Halo Reach you were able to customize the mongooses skin color via selecting TEAM COLOR in options. But make it for other UNSC vehicles as well like Scorpions, Falcons, Mongoose, Convoy, Warthogs, etc.
That would be difficult just for the fact that, Halo Reach firefight map Holdout had rain. And it was a good battlezone map, but all the rain caused lag. Imagine (What is it now on Halo 4 max players? 18? 20?) 18 players in one lobby where there's a snowstorm, think of how laggy that would be.