I'd also love to see a mega expansion based solely around supernaturals.
I can see adding a basic skill set similar to picking vampire powers (with at 3-5x more options overall) where you could customize your character thematically (werewolf, witch, genie, faery, etc.) instead of putting so many resources into creating individual supernatural frameworks.
Then add a TON of CAS, build & buy items. And maybe add a few extras to vamps & aliens in the pre-expansion update.
I'd much rather see more fantastic elements in the game than the same boring, mediocre day to day stuff like "laundry" themes or the latest celeb expansion. Don't we play games to avoid chores like these?
I also had the celeb expansion in S2 & hated it. I did the celeb stuff once & never touched it again.
(The celeb intrusion, on most other aspects of the game, annoyed me - much like how many people have a problem with vampires constantly intruding on their mundanes.)