After less than a year on the server I already had everything vanity had to offer to me as a stone rank, vanity is there to give you a goal to work towards, imagine a server where they give you everything at the start and have nothing to work towards ? It is pointless and a server you get bored of quickly.I agree with you, also there is a good percent that you'll get an item you already have. To my opinion, they should compensatie you if you already have the item.
4/5 kills is a little bit less, because then the rarity changes alot. However top killer would be a good option.