Jungle Lanes - Rotating Game Mode - Jungle Creeps for Minions
I was thinking about the rotating game modes, and it seems there are just 3 main kinds. Poro King, which is basically just ARAM, (maybe ascension idk if that's still in rotation). Then the two kinds of URF. These are good, but in terms of a more traditional game with variation, I think that Jungle Lanes would add something a bit more structured than these random/rapid game. Jungle Lanes plays just like a regular game, but with jungle monsters replacing lane minions.
Melee Minons - Big Wolf or Big Krug ; Ranged Minions - Gromp Cannon Minions - Dragon Super Minions - Rift Herald
I thought of this because the minions just seemed to fit very well into the roles. The thing is IDK how much damage a dragon would do to a wolf or a gromp, but this is a sort of "crazy" game mode that allows for a bit more structure and reason than the other ones which are pretty random. I know 3v3 and Dominions were unpopular, but those were a least different takes on the actual game, rather than quirky modes. All of the other events had to do with specific skin releases or other themes like that, so I think the advantage of this one is that it produces a bit more regular-style gameplay with a twist and doesn't depend on skin-releases to be put into the rotation.
It's basically like normal but the minions are extra dangerous and this sort of make lane-trading much more risky if you get aggro. The increased gold would lead to quicker games, and that's something I think people like about the featured game modes.