Bit of a rant about Rotating Game Modes not being frequently seen.
I get that you don't like these game modes even though for some players they are the best game modes, far superior to the normal 5v5 summoner's rift mode. I'm not sure why, maybe you have the same problem with them as you do URF, and feel that people leave the game afterwards after realising that your normal game mode isn't that fun. You tackle this the completely wrong way though, players find these modes fun and want to play them, you say no for a silly reason, of course, people are going to quit. So instead, say yes, allow people to play these game modes, support these modes and allow players to play all sorts of game modes within your games. Think of Overwatch or some other game, they constantly have other modes available for players who want to play them, as well as ranked games. They don't go, oh that's too many people playing arcade, we must remove it! No, because that's ridiculous. There hasn't been a rotating game mode in weeks and even though, looking at BunnyFufuu's uploads, the next one is ARURF, this doesn't justify the weeks upon weeks of not having a game mode. If you want to have rotating game modes, fine you do you, but at least have them every weekend instead of whatever game you are playing with your players right now because it isn't fun. How I wish you could have them as permanent options, being able to constantly play Nexus Seige, ARURF, Ascension, Dominion, or even Blood Moon! Even Blood Moon is better than nothing. Yet I know you won't make them permanent, but the least you can do is have them every weekend. For the majority of your player base that is casual, that plays to have fun, that doesn't give a damn if marksmen are viable bot lane because they didn't play them there in the first place and were doing stupid stuff like Garen and Darius. You need to, not only as a business that wants a player base, or as a video game company, but as what you set out to be Riot, to be this company that made a game for gamers, you need to make a game that meets their needs, not your own. If you have made something fantastic, super fun, such as these game modes and you take it away from people because they won't play your other creation as frequently and you take it away, you are just asking for them to quit, which just gives yourselves another reason to justify you taking these game modes away, when really you are just creating the same problem over and over again.
TLDR; At least have rotating game modes every week if you won't have them permanently because your majority casual player doesn't give a damn about ranked and your summoner's rift, and if they do they're hardstuck silver somehow anyway.