I've put a lot of thought into this idea and concept. I really think with the right team this could drive the player base to be more active in-game and maybe even increase the player count.
Basically, to avoid Nintendo or anything, it's just * Pet Handling *
Once players receive a pet, they can now duel it against other players' pets. in a designated area * like adding it into the duel arena *
Each pet will have it's own unique fight style with attacks * etc range/mage..etc * You can level that respective stat to 99 just as a core skill, so now, My vorki can level it's mage to 99, if that's the style it fights with, each pet only has 1 skill. - You can win untradeable cosmetics for your pets with so many wins and of course a cool cape at the end, but I think for the cape you have to get 3 pets to 99.
Which now means players are driven to grind bosses for pets, so they can try the new skills, maybe new players will see an add an try the game just to try that.
Players are worried about the perfect 24 skills, No worries, this will be added underneath the total level an you click to open its interface as you would any other skill
this is a rough concept but again with the right team this could be such an amazing skill!