Yes please, to a ghost revamp. Have asked for it many times before and will ask again, thank you. :)
I'd like to get rid of the ghost needs unless under special circumstances, like, say, the friendly family ghost who thinks it's still alive and lives in the house doing what it always did in life. Eating at the table, showering, etc. But it should have a "startling" effect on Sims when encountering it, although can be befriended and made an "official" member of a household.
Otherwise, I love a lot of the suggestions in this thread and I'd really like to see some other ghost varieties. Haunters, wanderers, restless dead, Reapers... Maybe a few main varieties? These "types" could each serve a different purpose. For example, the Reapers, of course, would work for Grim and help gather souls (new career!) and could get their new "uniforms", sporting varieties of the classic, creepy death robes and withered look of Grim himself. The Haunters could be tied to the location where they died, possibly re-experiencing their death, scaring Sims, occupying empty lots and graveyards, but possibly have a way to be put to rest by a living (or Occult) Sims. The Wanderers could be like what we have now, NPC ghosts, but without the needs. The Restless could be the "family" type, who settle into their old lives but maybe also can reproduce like in Sims 3, so they can be played like regular Sims. And, of course, I agree with @CAPTAIN_NXR7 about botched resurrections and the return of "real" zombies, like in Sims 2. Oh, and also, please add a few appropriate cross-pack powers to the other Occults, like death/resurrection spells, special Occult ghosts, etc, and allow children and toddlers to be ghosts as well. o:)
There are so many ways Ghosts could be expanded. They have been in The Sims since the first game, haven't they? They deserve their proper place amongst the bigger, better Occults. Some extra things in CAS I'd love for them are ghoulish makeup, tattered clothing and shrouds, deathly skin types and textures, even strange faces or "heads" (or headless) like they did with Aliens in the Batuu pack. Ooh, now that I think on it, please, please, please can we have a headless effect? The Headless Horseman is one of my favorite "haunters". Would LOVE to play one without a mod. And also, some wispy and weird hairs and strange tattoos/body marks.
I love ghosts (if you haven't noticed). They scare the bejeesus out of me. I love them in films and books and stories, of which I have a collection. I live in a city that has a history with many haunted tales. Please give our Sim Ghosts some love. <3