"I want stuff faster"
"I want to be done with raiding"
"I want unlock sooner"

Multiply this by the amount of people raiding at any various skill level and you will see an exodus of gamers.

Give them a reason to leave sooner and they will.

The devs know what they are doing to keep people around for longer. Yes they want to "respect your time" and say "go play other stuff if you want".

BUT they also don't want to artificially give people reasons to NOT stick around longer either if they want BiS savage gear pieces.

This argument has been around for as long as raiding in this game has been around for. It was worse before now before the books/token system came in.