Instanced Dungeon Que System

I keep seeing everyone go back and forth on this class balance issue and Kachi I like the thought of your idea with combos, but how would you make something like this work on a day to day basis? Are we saying that, in a class v class balanced system, any combination of classes will work for any encounter?

For example: I want to fight Bahamut and it takes an alliance of 18 players. I've found 15 DD, a tank and 2 BLM and no whm seeking to group. Now, in a system like FFXI this would be impossible since there isn't a single true healer and way too much hate coming off the tank. If we're running your proposed system of class balance, how would you try to make this work? Would that setup be impossible and would I then have to find a WHM? If I do, then aren't we back to the trinity in a way?

I really am asking out of curiosity, as I'm not quite able to wrap my head around the alternative.

Edited, Jan 10th 2013 8:46pm by IKickYoDog