To be fair, not all he talked about WoW was Blizzard's fault. It is nostalgic to look back and say that world was smaller, you can meet everybody, flying mounts killed it, etc. but to be fair, people demand quick travels, etc. in games these days. Casual gamers have way much things to compete for their attention. Also leveling stuff was unpopular as hell. Everybody wanted to get into Battlegrounds when they got to x9 lvl and then leave it for another 10 lvl upgrade. One shooting someone who is lower level is fun? Yes, but not at receiving end.
Said that, as always, devs can go smart way, and they can swing in one of completely opposite directions. Blizzard wanted more casual money and they pushed WoW in more casual direction. I am not totally sure flying mounts was issue. Not everybody wanted to do open world pvp. Not everybody is in emergent gameplay. Yes, I played WoW during classic era, it was fun for a while, but it was just a period, that player interaction, while being interesting, did not hold my attention, especially if I played alone. It is essentially a 'friends' game, which is it's huge blessing and curse in same time - as any MMO essentially.