After Blizzcon I think there will be WoW2 around 2030 and one thing I'm sure about is that I'm not doomer.
First, it will be time to switch 25+ year old engine. You think they are gonna remake 1500 mounts, 3000 pets and bazylion transmog pieces?
Second, WoW2 is opportunity to shake a lot of ground stuff. There are simply things you can't do in expansion, for example you can't move race to different faction, remove archaic systems like TBC flying, etc.
Third, I think we all want to end WoW1 on high note, not inventing new threats every expansion. I really hope 13.2 boss will be finally Sargeras himself, you can't go more iconic than that (and thankfully this card wasn't used in Legion).
And most important - they can do interesting stuff in Midnight and go ALL IN in Last Titan from character progression POV. It's like Legion, but you don't have BfA hangover after this. I'm thinking about absolutely crazy stuff, something like full legendary gear to even start progressing final boss.