Maybe if there was a way to mod the game, I know they won't do modding literally. I mean like putting tools in the toy box, tools that let you change and do things to existing characters. These tools can include but are not limited too:
Animator - You can animate a character by using a set of animations, this tool will let you be able to set up actions for certain parts in your toy box. It can even go as far as letting you change a characters bone positions. Such actions can include: Walk, run, climb, jump, raise arm, dance, faint, etc. Similar to the action enforcer toy.
Effect creator - Allows you to make custom affects, by changing things like particles sizes, lifetimes, color, speed, amount, shape, sub particles, etc.
So basically like toys we already have, just far more advanced. Maybe a toy called the action creator will allow me to set up specific moves a character can do at a certain time in my level or anytime, it will ask for an animation I made in the animator and a couple of particle effects(Charge effect, blast effect, etc.). And I can have the ability to either summon enemies from a ally wave toy or set up a damage zone with visible circles and cylinders. I can even set up the particles to do damage them selves, like missiles.
So basically toys that allow the players to create such content, and then hold contests and such.