This has nothing to do with "rank" other than don't bring it up as an objection.
Some of us hate ... I repeat hate ... ranked play. We have no desire for it, we don't play it. There is nothing that we see as a benefit to it.
Read that over again. And if you are about to say something about "when you get to higher levels of rank ..." stop. Read it yet a third time. And keep doing so until it sinks in, that rank means NOTHING to us. Now that you know rank had no meaning continue.
I have played just a very few ranked games, and don't intend to return there ever. Does that mean I have no skill? Don't think so, I'm very much positive in ARAM (win/loss) and that is being paired with people that I'm fairly sure are not very skilled. I've been asked if I am on a "smurf" account (I'm not) but I do play fairly well. I on rare occasion get sucked into a normal on S.R. Mostly from people I know IRL that play pvp. And yes, it is "get sucked into" for the most part. Generally, that is less toxic ... I know at least one other person and they know me, so it stands they aren't going to say things that start out "you idiot!"
While I play ARAM and co-op vs. AI, I know people that will NOT play even ARAM because of toxicity from players that will be there, but only because they are practicing for ranked ... they only play bot games. Given the few times I've seen real teamwork going on by ranked players in co-op vs. ai, either it is they don't feel they should "it is only bots" or "it is only aram" syndrome (and almost always by people ranked at least silver) ....
This game has more unranked modes than ranked. So it is about time that Riot pays attention to those of us that don't want ranked, nor do we care about ranked players. We care about the game and what happens everywhere else. We want things that yes, they might not be good things in ranked play. We really don't care ... they don't have to be in ranked play. So there needs to be a little bit more ... flexibility in the modes. Things that would be good to increase enjoyment for people in modes that have nothing to do with ranked ... so the "rules" for ranked and unranked play need to be different.
I've seen that you already do this a little ... ARAM has mark/dash to make melee champions OP and nerf the devil out of squishy champions (you aren't going to see that in ranked ... close from 1000 away, hard cc on a squishy, and boom; one less squishy). So it isn't like you can't do things differently. So put some effort into it. Make it so that outside of ranked is truly outside of ranked.... Allow reporting for outside of ranked activity that has nothing to do with inside ranked. (If a player is unsportsmanlike in co-op vs ai, they can be banned from just co-op vs ai ... or any other mode for that matter.) Behaviors that might be "okay" or even desirable in ranked play can be toxic in other modes. ARAM is one (it is pure teamfight from the start). co-op vs ai is another.
What things can you do that just won't work in ranked that would make the other modes more enjoyable for those that play there. spend some time on it. Get to know us.