Just beat that medical wing rooftop mission listed at level 14-18 (I think) mission with a group of my friends and we were all level 9-12. Man, that was a grind.
I got real good at sniping, but this game still feels the same like when you first started, not much versatility. If anything I like the team work aspect of it, but I think a lot of games have that too.
I'm gonna stick around though and see what those other skills do. If it still doesn't bring character to this game, I might call it quits.