There are a total of 26 ghost types, 13 of them being NFEs or other forms such as the rotoms and giratina-O. Plus, I dont think you should count arceus in ghost form as a true ghost type.
Ghost types I believe have the best lore and some of the best potential but there are so few! I say we need more ghost types, maybe a fire ghost type, other then the living microwave.
So, discuss, do we really need more ghost types?
Lastly: Drifloon FTW!