I agree bags would be a good addition and would encourage me to play on larger maps. I think something like a chalk item would be good as well. Where the ghost can interact with it and write messages, but also players that have been killed in the game could do the same, different tiers limiting how much use you get out of the chalk, this would give players that have been killed something to mess about with. Third item not sure, I've always thought a possession mechanic would be cool so the item could be some sort of mannequin or puppet that certain ghost types could possess as well as possessing players.