I sort of disagree here. Where do you draw the line? What happens when someone gets stuck in an off role? What happens when people know how to play a champion but they did most of that playing before champion mastery came out?
I currently only have 3 champions above rank 2 in champion mastery. One of which I no longer play in ranked because despite something like 60-70% win rate in normals with him I'm sub 40% in ranked (doesn't matter that I do well with him, I seem to always get bad teams when I try to play him).
That said, I do perfectly fine on a wide variety of other champions. I've practiced a lot of them too - I'm only mastery level 2 (or maybe even 1) on Caitlyn even though I mained her in season 4. I'm only mastery level 2 on Leona even though she's my go-to support.
The big thing is, I don't play all that often. I don't want to have to grind at least 2 champions in each role to level 3+ mastery (what if the 1 gets picked/banned) to play ranked when I'm only going to choose a champion outside of the main 3 in 10% of my games? And when I'm perfectly competent on those other champions anyways...
Not to mention, champion mastery is no true measure of skill. A player who sucks all game and gets carried to a 55min win in a game that should have been a 20min stomp is going to get a lot of mastery points relative to the player that did well and got the 20min stomp, and even more compared to the player that did well but had garbage teammates and managed to draw the game out to 55minutes before finally getting beaten 1v5.
On one side I understand that you don't want people pulling out a first time pick in ranked. And I agree with this, but ultimately if you're stuck in your worst role and happen to have all 2-4 of your go-to champions for that role picked/banned does that mean you're forced to dodge? Or play your main from a different role in that role? I'd rather go first time with a legitimate top laner than bring my mid laner or adc to top... Each individual should be trying to maximize their individual chances of winning - it's unfortunate that some people play ranked without this in mind (man, the people picking Kindred in ranked the first couple days after release is sickening) but ultimately they'll drop sufficiently lower in elo that their game-ability is better than their MMR represents because they're playing on unfamilar champions. It should balance out in the end.
