This is the most ridiculous thing I've ever read.
The things his team was in charge of, i.e. systems, improved massively during his stint, and they've been improving ever since then. WoW has been lackluster the past few expansions because of content droughts and neglecting core gameplay like 5-mans.
For all the people crying "homogenization", take off your nostalgia glasses and look at the abysmal state of class balance in Vanilla/BC. Entire specs were just complete jokes. Lolret? Oomkin? How about a warrior spending an hour autoattacking an invulnerable mob in Blasted Lands wearing Intellect gear before he could use a raid drop because weapon skills were a thing?
I bet you're the same people crying about classes being "completely non-viable" because there's a 10% variance in throughput on a patchwerk fight.