Since the S3 will start very soon, as a player at all time (well, not exactly but at least at kog maw/ xin zhao), I would like to suggest a little voting mechanism in the selection of champion @ rank game - solo/duo which the voting can stop people from, well at least before the start of the game.
E.g. Summoner 4 wanted to take a specified champ/lane to play while the decision, from other player with conflict to the previous was agreed upon by the other teammates.
Summoner 4 started to argue/ yell/ declare to troll etc. that may potentially affect the game result/ performance of the whole team. Any other of the team may start a voting mechanism to disband the team( back to queue) and, at the same time ban that specified teammate from game for awhile/ other more serious punishment/ w/e so that the game may at least start from, well a more peaceful environment.

You give the majority FAR too much credit. There would be nothing stopping premades or just general groups of *******s from trolling the hell out of some random unlucky person because he picked Sejuani or something completely benign. A votekick system is bad enough and will probably never get implemented, but putting a time ban on a specific person as well is completely ignorant of the concept of "just cause."