I also came up with what I think might be a really awesome new gametype. It is effectively Invasion from Halo: Reach, but much more vehicle centric.
The game would basically be a Covenant Invasion on the Reactor map, with Wraiths, banshees, and ghosts spawning up on the hills outside the map.
There would also be forged Dropships with turrets on them, as well as various covenant power weapons to supply the invasion force.
The humans would have bolstered defenses such as a tank or two, gauss hogs, missile pods, rockets, lasers, and other human weapons to choose from. They would also have increased barricades to prevent the Covenant from getting into the reactor as easily.
For the actual gametype I imagined it being Infection, starting with 50% zombies. Perhaps the humans would have extra damage resistance or shields, and the zombies would do slightly less damage to balance it out a bit.
That way the game would play out with the humans heavy handed at the beginning, but after exhausting their power weapons they'd get overrun by increasing waves of covenant.
It could also work with an Assault gametype, but we'd have to give everyone the same starting weapons and count on them using the supplied Armories to equip properly.
What do you guys think? I already started on the map a bit to test the plausibility of the set up and it works well.
I'd like to have some other people help collaborate with me to flush it out more, so if you are interested in helping out send me a message or comment here and we'll find a time for me to host a server.
Thanks for reading.
TLDR: Invasion gametype on Reactor with a lot of vehicles.