For ex, they can give you a good or a bad jungler. I've noticed for a couple hundred games, I got consistently the worst jungler. It's very easy to check : I'm top, I let my lane push under tower, I wait for 15 mins. They don't gank. Not just once or twice. They failed to gank for several hundred games. Then I push for a couple seconds, immediately the ennemy jungler ganks. That's the obvious proof of a huge gap in skills. It's also funny when I have a premade jungler and we immediately get kills because he ganks appropriately.
Now obviously the usual conceited ridrones are gonna try to deny but your wishes don't weight anything against factual experience.
Seem totally %%%%ed up to me when a game that is supposed to be based on skill is in fact based on the choice of the game