Well I've seen some Japanese mmo's do this and seems to work wonders for them and it would be very cool...
Have a person control the boss.
Everyone says the AIs need improvement which they do but the thing is these new AIs I would think would cause lag for everyone so I thought if a person were to control the monster it wouldn't cause lag and it would be MUCH harder, if this were to be implemented the boss in question would have to have it's uber amount of health and str and so on lowered to because the person controlling it could now think of strategies.
the only problems I can see with this is
~paying the guy who gets to pwn the poor guys he went up against
~and that how to reconfigure agroing the boss (perhaps make set rules the person who plays the boss such as target those who have done the most damage to you.)
The pros to this though to me out weigh the cons
~whole new game challenge
~allowing for team work to be more essential
~make the bosses more realstic(game wise)
~never the same experience with the boss(unless he spams that one attack yet again restricted by some rules)
perhaps this has been suggested before but I think the idea is a pretty good one.
PS posted here not suggestions due to the fact this has to do with monsters and a change with AIs