Hello there fellow summoners,
I think we could almost all agree that the removal of Dominion was a very bad idea of some of Riot's employees, right? This game mode was, in my opinion, very underrated, especially by Riot (otherwise they wouldn't have removed it). The reason behind this statement is that Dominion had quite some purposes to the community:
1. Many people REALLY enjoyed playing Dominion
2. People were able to test champions and/or train their mechanics
3. It was a fast game mode, so if you had little time to play you could play Dominion
4. Dominion had a really good effect on tilted players, it basically was an untilting game mode.
Therefore it was a shame that Dominion was retired in 2016 due to the low playrates. In my opinion this game wasn't about the playrates, but about the effects and purposes described above. And let's ask ourselves this: Many people believe and say that League of Legends started to fall in terms of toxicity and gameplay since season 7, which's preseason started december 2016. **I take the courage to say that this is partly due to the removal of Dominion.** People have no ability to do a game which only takes about 10 minutes after they had a shit game on Summoner's Rift. The only thing we can play now that is short is ARAM which, if you're lucky, end within 20-25 minutes. (And ofcourse there are the rotating game modes, but they have no permanent effect because they are temporary).
So, honestly, I would vote for the return of Dominion, regardless of the huge amount of time Riot has to put in it to bring it back. They owe us, the old playerbase. So please Riot. Please listen to thousands of people that actually miss Dominion.