You also discount human nature. I've noticed all of those things, believe me. I also agree that the current Hamidon raid has spoiled people. That is why I suggest leaving The Hive the way it is.
But for those who want to do it as it was on live like myself would be more motivated to keep it together. Because there would be fewer people, there'd be more personal responsibility. People stay at the rock and AFK because "Eh, there's 150 other people here, it doesn't matter if I go help them." If you limit it to 50, those same people (if they bother to come at all), will be more motivated to help, and will also be more noticed if they don't.