Dominion
I think Dominion over the years has not been a common game mode that people would actually play. People had even volunteered Dominion's life to keep U.R.F as a game mode. I say you should have like a thing that makes dominion more common. My idea is to increase the reward system on Dominion, like maybe if you play 10 games a day you will be rewarded nicely with 200 RP which you can only do once per 3 days (So people would still buy RP). And maybe it could just be a random champion that is under 975 RP or maybe is in the 250 RP range to the 975 RP range. Or 580 RP range to 750 RP range whatever tickles your fancy riot, but this is just my suggestion to make Dominion more popular. And maybe just make this a 12 day even so players have a chance at a possible 4 champions over the 12 days. I bet you there will be a demand for dominion after that even because people will see how fun Dominion can really be. Anyway that is my opinion on Dominion and what you can do to make it popular, anyway cheers :D