Resource gathering mode?
Okay, so instead of the normal 3 lane mode, you have a mode where you capture gold generating nodes. Gold can also be used to build turrets, buff minions, and even place minion spawning spots, and respawn areas. The goal of destroying the enemy base is essentially the same however.
Basically LOL but with RTS elements mixed in. Maybe you can also command/direct minions from spawn spots that you built.