@Jokubas fantastic breakdown of the logos.
Yeah, Jimmy Lo's art for Bastion looked great!
If a dragon expansion was made in the 2000s, a rainbow colored logo of blue/red/green/yellow/orange and black could have worked to symbolize the 5 dragonflights, but today that'd probably get nixxed by the marketing department due to giving off the wrong connotations.
The EoD logo was pretty cool, though.
There is still the other side of Azeroth. It has been implied that there is something going on there, as ships that sail too far into the Veiled and Forbidding Seas do not return. Warcraft lore also has more than enough meat to support an underground expansion with 6 zones, as the adventurers trawl through Drogbar tunnels, Y'shaarj's dead guts, Nerubian cities, meet the Titan Azeroth herself, etc.
Fighting timetravelling clockwork dragons powered by the souls of demons would be pretty rad. Dunno if that could carry an entire expansion, though.
Silvermoon being repaired would be great, and so would be seeing the Exodar up and running like it's been in lore since Cata. I don't see how Gilneas and Kezan could be revamped, though.