I know that this issue is present for every player of league of legends, and it's very annoying.
Many, if not every match that I play there's more than one person that wants to be either mid, adc, top, jungler or support, and this in most of cases is just decided by who "picks first" as the "player made rules" set it. But sometimes somebody just wants to play that champion and locks in, so the other person who called it first also locks in because it was their right to play with it, and this causes a trouble for the rest of the team, making them in most of cases, lose.
I came up with a good idea, and I really think it should be considered because it will prevent that problem every time. (unless it's a troll who just wants to make you lose to have fun, no matter what champion they use).
It is a system for the queue that before you start getting matched, you chose what you will play. Of course this will just work for the normal META and there could be a "free pick" queue too, just like it is now.
In this, say somebody picks adc, then the system stops counting every other person who picked adc to match them with, and this is done until adc, top, jungle, support, mid are picked.
For this to work, every champion would have to be classified as whatever it is, and if somebody chose support, they would just be able to pick the support champions. This goes for every other champion class.
Maybe just enable this for level 30, since at lower levels everybody choses what they want.
Please comment your opinions! I really think this would change the gameplay.