You MUST have at least mastery 5 with a champion to pick them in Ranked

So lately I've met kinda a lot of people who play ranked games (both flex and soloq) like normals and it really pisses me off. Some recent examples: a Gangplank in his promo to Gold was actually first timing him. In the post game chat he said "i just bought it :D". Indeed, he didn't even have mastery 4. People pick champions like Gnar and Lee sin without even having mastery 4 and, of course, they suck with them. A Zed, this time in flex, said "I'm just trying this champ" (not even mast 4, in fact), "idc this is flex not soloq", "it's troll ranked not real ranked". In soloq, I've met many Yasuos below mastery 4 who, of course, only fed and did bad. This has to end, it's unbearable. Ranked games are supposed to be competitive, you play ranked because you don't just want to have fun, you want to win, you want to show how good you are, to prove yourself how good you are by climbing. And then you meet people who think they can just first-time champions who are mechanically hard to master (e.g. Gangplank) because they don't even really care if they win or lose that game. I don't know why they don't play normals, but this has to end. My suggestion is to implement a minimum limit of at least mastery 5 to be able to pick a champion in a ranked game. It makes no sense to play in a competitive queue if you don't even have enough experience with the champion you're going to pick, there's no justification. It practically means people must be forced to try a certain champion in normals a minimum amount of times to be able to pick that champion in the ranked queue and, to me, this makes perfect sense. Think about it.

TL;DR People must be stopped from picking champions they are completely unexperienced with in ranked games, I suggest to implement a prerequisite like having at least a mastery 5 with them for the pick to be available.

EDIT: I can see many people disagreeing and this just proves my point. Stop being arrogant, you (and I) are not so good to just go and first-time a champion in a ranked game and play it as if it was our main. We're no Pro. Deal with it. I still can't find anyone who actually disagrees with me and proves his point, because** what's the point? "I'm good enough to play everyone I want whenever I want"? Pretty arrogant**. If you don't care about winning or losing and just think that you can try a champion in ranked, you're an idiot. Play normals, leave rankeds to people who care. That's COMPETITIVE play, if you want to try new champions and strategies there are normals. If you want to do your best to climb and actually play to win, there's no justification: you play champions you know and understand at least a minimum. There's literally no justification. Get out of the ranked queue and leave the competitive play to people who actually care, if you're not gonna play it at your goddamn best.