Big Team Heavies is the mode I always played in previous Halo games when it came to just out all chaos. Just a match where you actually have tank spawns and air combat, adding on the 12-player teams sounds like a game where dominant vehicle use is the play, instead of camping with a skewer to cheeze a spawning wasp or some crap.
Of course, a complementing map would help, but I still see it working out.
Maybe if they allowed PC players a separate set of tank controls that are simplified to what we’d expect from a game that allows you to both drive a tank and operate it’s turret perhaps.
I don’t even like getting into the Scorpion tank, usually I snag it just so I can give it to a teammate to keep the enemy from getting it.
Big Team Heavies was great, might get something like it it in certain infinity’s new mode that’s coming, think a remake of avalanche is coming, called Frigate, which would be goos for it
As soon as we get the Custom Game Browser and Forge I will have 2 different setups for BTB Heavies! Guaranteed!
One for Capture The Flag
One For Stockpile
With lots of Heavy Weapons and Heavy Vehicles!
Example For Breaker:
Right Now I can only do the Weapons till we get Forge. Here is my setup now:
Starting Weapons: Hydra with extra ammo - Rocket Launcher with extra ammo.
Movement set at 110% including Sprint - Low grave so you can jump higher on to buildings - Max Shields set at 70% so the crappy weapons even can kill people. Real fast Reload speed set a 144%. In CTFthe flag carrier runs and sprints and the same speed as everyone else! Not sure if you can PM people in these forum but if so PM me and I’ll boot up the game and show what I have so far in Breaker for CTF!
The kool thing is if you grab a Hog then get right next to a bot the bot will get in the passenger side and on the mini gun automatically 
That is just for Starters!
Peace! 
Sounds like a fun mode
That new map was pretty vehicle-oriented back in Halo 3. It would definitely be a great time to introduce Big Team Heavies again.
Ya can’t to the the Custom Game Browser and Forge!!
Peace!
Heavies is what BTB is lacking. Maybe that is what 343 will focus a season on in the future.