Natty DL said:
Pokemon, it would be full of people in the Hoenn starting area saying "SO I HERD U LIEK MUDKIPZ?" But it would be fun otherwise.
There is actually a Pokemon game called Pokemon: Den of Ages. It's free, and not popular enough to be trolled.
Personally, I think TES: Oblivion would have benefited from (if nothing else) an online bazaar. That would have been nice. Past that, I think it would be awesome if you could join your friends in their current games. That way you could muster a band of well-equipped PCs to stop the Siege Engine, fight Mankar Cameron, and defend Martin on the way to the Temple! How awesome would that be? Plus, for those of us who don't like having all those Oblivion gates everywhere, you could not start the main story once you escape the sewers, and play that entire campaign with your friend in his realm!
Also, since the missions of Mass Effect 2 are set up so that each mission plays like just a normal game's level (as opposed to ME1, where it was all free-roam and such), they could have easily made it so that you could invite friends to join and play as one of the squad mates. Honestly, that would have added so much to that game, and they just didn't bother! A POX UPON YOUR GOATS, BIOWARE! A POX I SAY!