I actually think some PvE assault and defend maps would be interesting. Maybe set them up like fire bases or outposts that need to either be captured or defended. The assaults could be straight forward go in and kill all of the defending units with a mini boss at the end. The defense missions could be a wave defense of increasing difficulty where the fire team goes a set amount of waves with an option to continue or quit. Maybe also set up some consoles to defend that activate and keep automated defenses running, and the capture of a command console or team wipe is a fail . Have these instances start at a random time with varying difficulty levels. Maybe enemies on earth could be relatively easy and get more difficult as you advance through the other planets similar to the progression of the story (assuming there is one). Each instance can last for a set amount of time (maybe a day or two) and keep track of the total wins and losses. An overall win in the guardians favor could then have a positive impact in the City like things cost less and better gear could be purchased, and a loss could have the opposite outcome. Something like this could give all players a sense that they are fighting together for something and that they have some control over the dynamics of their environment. In a sense we all succeed or fail together. I also apologize in advance if the grammar sucks. I'm down with the flu, and was rambling a and brainstorming.