There is a old minigame that died out due to it being only on a single server called Super smash bros which had a class system and a multitude of different class each with their own unique abilities that allowed for varied 1v1s 2v2s or even 1v1v1v1s. It used to be hosted on a server called Minecade and I think it could be brought into Manacube as an alternative to Kitpvp. It can be configured to be played in the regular vs mode or a small tournament mode in which 8 people participate to find an eventual winner. A good monetization scheme for this would be gems/points/cash from winning matches and then are used to buy kits for a certain period of time but if you want to own all the kits or 1 specific kit then it would be bought with harder currency. Global rank or server specific rank could bring perks like choosing a map, time of day, or have its own monthly payment to access all classes. With crates included for cosmetics on class weapons and armor.
Old snippet of info from a Sethbling vid in 2013 showcasing the original server.
(8) Super Craft Bros Server Update -- Minecraft PvP Server - YouTube
Old snippet of info from a Sethbling vid in 2013 showcasing the original server.
(8) Super Craft Bros Server Update -- Minecraft PvP Server - YouTube