I was messing around on Halo 4 via Halo: The Master Chief Collection last night, and I decided to create a gametype and map. The gametype is called Shotty Thrusters, and it’s a fast-paced Infinity Rumble variant with shotguns and unlimited Thruster Packs (with a few other alterations, such as lower player gravity, thrown in there.) I also threw together a map for it called Shotty Thrusters Arena, but I find that the built-in map, Relay, works well for the gametype. Both can be downloaded from my file share, and I made a quick video showcasing the general idea (linked below.) Enjoy!
I tired out the game mode, its really awesome!