I'd like to keep them but I don't like how they work in TS4. I don't like seeing them in nightclubs, calling alive sims vie phone, texting, congratulating birthdays, promotions, asking on a date etc.
TS3 ghosts were awesome. They were creepy, could only be seen where they are buried, I miss TS3 ghosts and cemeteries.
TS4 ghosts are like a joke. They are way too alive and active, they are not creepy at all, they are not ghostly enough, they look like haribo gummy bears and get involved with alive sims lifes way too much.