TLDR:

"I am a casual, I should be able to get to, and kill the final boss just like the hardcore players. Only repetition should determine the gearing of players. WoW does a good job with this, all players can group up on a whim and do dungeons without having to do any work."

Yeah, I'm a little snide, but its because I put a lot of work into my character. Time = reward in MMOs.

I don't agree that ANYONE should be able to do ALL content.