YES I HOPE SOOOOOOOOOOOOOOOOOOOO!!! PLEASE NAUGHTYDOG!!!!!
But some time ago they said in a interview, there wasn't going to be Co-op, only multiplayer.. but i hope they changed there mind, cause it was a long time ago.
Yes, I'd like a co-op Adventure. But not a tacked on version like Uncharted 3's. Story telling isn't neccessary. All they need to do is designate point A and point B and make it difficult to get there.
- Also, if they are to do a co-op mode, they shouldn't be afraid to make one difficulty setting to be ridiculous, for the hardcore players. In Mass Effect 3 people belived Platinum was impossible. Only the best of the best could complete it, and I find no more satisfaction in proving the non-believers wrong.