In KitPVP, add a custom plugin that, when you type /duel (player) it will send a request and if the player requested types /duel accept it will open a GUI to each player to select a class from any KitPVP kit(every player has all kits in here to make it totally equal). It will also select a random arena that are all 16x16(1 chunk) for the players to duel in.
Party chat is already planned, but I would like if we could get it sooner.
Add a couple more KitPVP maps, some that have kits that are exclusive to that map. I think it would be cool to have a map with like sky islands and maybe a jungle/tropical area.