Free For All
I think that a free for all mode would be interesting. You would have 6 champions instead of 10. You can use the red buffs, blue buffs, and two bases as spawns. You can shop each time you die and only then. You have health packs like it did in Dominion. Lessen the amount of space in the bases to make the space fair. Add a few bushes. Take away top and bottom lane. Just an idea. Either way, free for all as just a rotating game mode seems fun..