What do you want in a multiplayer server?

Hello! I'm currently working on a multiplayer server, and I've already found a few things that barely any server has. I do not want to go out with these yet, but they will probably be awesome. I'm making a factions / PvP server... I know what you thought right now but wait, it will not be any normal factions server. It will have several unique features ( I've already made one myself, and added some that a few servers has!) Now I just want more suggestions! You can suggest ANYTHING to add! Also please note that I won't add features which gives some players unfair advantages.