How about a wave-based PvE game mode? (Similar to Halo Firefight or Call of Duty Zombies.) The gameplay would be similar to that but with the added point buy system and weapon and equipment vendors scattered around the map to help players understand why they have no equipment, primary weapons, or unlimited portals. The enemies could be themed as robots, with each type representing a different faction, (Aeros could charge at players, steal power weapons for allies, and stun your teammates, Meridian could heal and speed up allies while picking off your teammates from a distance, and Sabrask could have higher health, throw grenades, and activate its shields when on low health.) We can get into contact if you are interested in the idea and I could expand on it more. My discord is zachtheaxolotl.