I would like some impossible scenarios added that are ranked with some kind of timed survival or points system.  Did you ever play the krogoth encounter mission when it first came out everyone thought it was impossible and I dropped a large amount of time in it figuring out my own solution (before you could just you tube search the answer) adding some kind of ranking system maybe like modern warfares coop ranking maybe 

you could add them as single scenarios that can be brought or an add on pack like with ta with some added plot to single player.  It's giving the guys that like banging there head against impossible odds something but also keeps inline with your core story.  

Maybe be if you have a giant whiteboard in the office with potential future ideas just jot that down in the corner