Props to this guy
League System, Matchmaking and AFK Players. - League of Legends Community
I was googling around when I stumbled upon this post.
Just allow us to queue up for our main lane. Positions clearly stated in the lobby above the player names. Keep the standard option of queuing with no preference, for those who really don't mind where they play.
2 years later, it finally happened and I love our role preference system.