If the other mobs are normals or strings, DPS can solo them in a small amount of time while taking minimal damage. This will greatly reduce stress on the healer (since some of those mobs may be hitting healer if they havent been hit yet) and the number of mobs you have to worry about holding onto.
In fact, operations trash is about the only time that DPS are supposed to be attacking what the tank is hitting. And frommy experience, the trash in 16man is more annoying than 8man, and the trash in EV and KP was not any easier than the newer stuff.
So yeah, I guess I disagree with pretty well every point you made.
maybe you should learn to read then .. it seems like you're agreeing with me.