Should honestly complain more so about the people who no lifed and did speed runs on Wotlk Classic for completing the content as fast as possible, then complaining there was nothing to do.
Blizzard wanted to keep their subs so badly they needed to create catch-up mechanics for those who played the game casually knowing it wasn’t a hard expansion until the Uld hard modes, then another easy TOGC raid before ICC.
To me they are the ones who kill MMOs more so than not.