Why not have a patrol mode with 6 players where there is a fortress or a base you can try to infiltrate. I'm not talking about a regular strike mission i mean this is really hard and takes cooperation and tactics. And there are parts where you need to find keys to progress, fight never ending enemies, race against timers where if you fail you have to go back to orbit to escape, save npcs and escort them to safety, random armies will attack the base while you are in it, and at the end you get a weekly loot chest that gives you a weapon like the vex mythoclast good. You could even use these fortresses for faction rallies or monthly events. Just something else to add besides more PvP events.