Change the properties of the ball in Splitball. Taking away the ability to portal with the ball while also making the ball more kinetic could be a fun change. By more kinetic I mean the ball could be modified to do thingslike be thrown further, bounce more, and roll faster. This could give the mode a more sports-like feel and also encorage more teamwork, ex: passing the ball, and more creative portal usage. Adding some sort of incentive to limit the time a player holds on to the ball could also be interesting.