I can play Support, but I'm not a Support main.
So after catching up on the goings on in League during a long-term internship out of town and fixing my computer and dealing with my Ranked anxiety, I've finally gotten around to doing my placements. Of course Game 1 we had a (unintentional) feeder, Game 2 had an AFK, Game 3 had 3 teammates initiate a Baron throw, etc. but what I really want to talk about is role selection for the new Champ Select.
I'm a Jungler. Have been since my 2nd week playing the game back in Season 1 (first champ was WW). I picked up Support somewhere along the line just to appease the children that threatened to feed because they didn't want to do it and I like that role too, but I'm a Jungler. So when I say my roles are Jungle first and Support second, it's a bit frustrating when my queue time is less than 2 seconds long only to be told I'm Support. Ok maybe having that happen once isn't a big deal, but it becomes a big deal when it happens 9 times in a row. As of now I'm a Jungle main that's played only 10% of my games in my main role and I'm really struggling to think of a time where I ever felt as stuck playing the same role, same 3 champions as I do now. Most of the reason I've had such bad Ranked anxiety is because the same thing happens in Normal Draft. I've been trying to pick up Kindred almost since their release so I've picked them in 100% of games where I could fit them into a team comp, but I only have them up to Mastery Rank 2 (along with Vi and Amumu, 2 of my main 3 junglers) because of how rarely I'm actually allowed to do something other than Support.
Look I get it, not many people choose Support or Fill (which we all know is Support 95% of the time anyway because not many people choose Support), but it seriously feels like I should abandon Support too so that I actually have a chance to play my main role. What I would rather have happen, though, is for the Matchmaker to spend a little more time, try to find the ones that are Support primaries first. They're rare, but I guarantee you they exist. If that means I actually have time to take my finger off my mouse button before a match is found, I'm totally OK with making that sacrifice. Conversely, if I end up getting my secondary role for 30% of my games or 40%, even 50%, that's perfectly fine, but 90% is ridiculous.
TL;DR: You say that the Matchmaker has a way of knowing when you haven't gotten your Primary role in "awhile" and adjusts to make you a priority for that role, but how long is "awhile"?