When I was just single boxing my lock I ran a 3 healer 5s team in S3 to ~2200 rating, lock/hunter/rdruid/hpally/dpriest. I can tell you that our survival was dependent on constant use of multiple characters CCing...if one guy dropped the ball for a few seconds vs 4dps you would easily wipe. In the current state of the game, I think you could have 4 guys drumping heals on someone and he could be still be exploded in a few seconds....anyway, If you get that far grats, now to win you actually need to outlast the other teams mana by preventing them from drinking more then your team, they will all split up and CC you as much as possible to get ticks of water in, with 5 players on your team it can be tricky to split up and stop them all...with 1 guy controlling 4 characters? Its just not gunna happen

P.S. playing outlast comps are pure fail anyway, matches are way too long