I always liked cannons. They look cool, are heavy, and will kick butt easily. Cannons used to be one of the most feared weapons on the battlefield. So I just had to put one in Silas.
I decided early on that I wanted there to be no aim assistance for the cannon. Instead, you have to rely on your wits and judgment to hit people. However, just one cannon ball can destroy a kart, so it is quite powerful in experienced hands. You can rotate the cannon head, and shoot either metal balls or slime balls. The metal is tough and will penetrate upon impact. Whereas the slime will stick to the ground and eventually fall apart.
You can see the cannon in action in the video below:
Also note in the above video a brand new level called "Barrel Cove". It is an ocean paradise. Each team claims it's own pirate ship as it's own. You must defend your flag within the ship and infiltrate the others. Classic CTF done water style.