New Feature For Riot to Add (please look or glance)

Its come to my intentions that every time i go into a ranked match people always fight on who's playing what. It shouldn't be hard but i don't know about how to make this feature. Simply its when you click PLAY and go into ranked or any match on summoners rift a drop box should appear and in that box has 5 roles. Top, mid, bot, jungle, support. what is the point of this? it will match make you with people that want to play the other 4 roles so no fighting and just deciding the team compositions i think this will be beneficial to almost anyone and everyone who plays League.

if its just me then let me know why this idea will fail thank you for your consideration Riot.