Is this even possible? Didn't they make it so you can't Q up with someone who is more than one tier away from you? So if you're bronze 1 the only possible way is for you play against 3 Plats or more is if there was someone lower ranked that you on the other team, which the game will not allow.
Are you sure you weren't looking at players who were Plat at one point maybe last season or earlier this season but no longer are? Also is this is a normal then I believe the answer is that they are MUCH looser with MMR matchmaking than in ranked.
As for your comments about the roles. Everyone needs to stop crying about getting off roled and trolling when they get off roled. It happens to all of us once in a while....learn the game. Don't learn how to play a couple champs, learn the game. Just accept that League is a game that rewards learning and pick a new game if you don't like it. I personally think we should go back to the system where you don't get to choose a role. Students of the game SHOULD have an innate advantage over one tricks and casuals. Also a big point that I think people disregard in this discussion but is very relevant is that learning the game from the perspective of other roles makes you better at your main role. So when you get off roled, don't troll or play half assed. Go try hard and you will learn things. Learning what goes through the head of a solo laner is helpful to a jungler. Learning what mid lane is all about affects how you play side lane. Learning how to support helps you ADC better. And so on and so forth, it's all tied together because League is a 10 player game with heavy interaction.
Catering to casuals and creating a nice little bubble for them to exist in is bad for the game as a whole. Blizzard listened to all the kids crying because those who sunk more time and energy into WOW had very clear advantages in terms of gear and cosmetic stuff among other things. So they removed some of the grind from the game, made it easier to get gear, made it easier to figure out your build and stat prioritization, essentially removed content. What happened? It nearly killed the game (this an exaggeration but you get the point). Now Riot has to focus on URF modes and releasing events and all kinds of crap that competitive players don't really care much about, all just to hold the attention of casuals. Like a parent shaking a rattle behind a camera to get their baby to smile for the picture.
Think of how sweet ranked queue would be if Riot took like %40 of the resources they dump into the "fun" modes and meaningless content, and instead spent it on things like balancing the game and quality of life changes.
