I would like to suggest actually recording scores for coop
they would be kept separate from single player and would list the names of each player involved
just because it is recording the score, doesn't mean it would necessarily have to impact rank, though being ranked as a team with people you frequently play with might be cool
pros:
more incentive to play coop
would be especially great if http://osu.ppy.sh/forum/t/88375 gets implemented
cons:
would have to store the scores and possibly replays
they would be kept separate from single player and would list the names of each player involved
just because it is recording the score, doesn't mean it would necessarily have to impact rank, though being ranked as a team with people you frequently play with might be cool
pros:
more incentive to play coop
would be especially great if http://osu.ppy.sh/forum/t/88375 gets implemented
cons:
would have to store the scores and possibly replays