Yeah, but kitpvp is a very low level gamemode in terms of developer work. It can be set up with little to not effort involved. Not to mention the sheer amount of customization possibilities kit pvp has. A different map and a different kit could completely change the dynamic of the game. Hell, you can even make a mock-OITC with it by giving someone a bow with power 1000 or something. There are so many possibilities that I believe it to be a good minigame to pick. You just need to gather up a group of people to think of the actual gametypes you can make with it.
my understanding is that there are kits (you do don't buy them, they are free and everyone has them) and you pick one and then you go into an arena and pvp.
