Add a "Report Pregame Toxicity" Option + P.S.
That guy who spams the pregame chat with something totally toxic. Those many, many players (now that New Champ Select is out) who ruin your game at the start by banning whatever pick you have previewed because they don't like it and want to force you to take something else. The 'polite' feeder who tells you what he's going to do pre-game- even if he's just doing it to get you to dodge, that's still reportable.
Even though it's not fair to penalize me for dodging to avoid these players (or for playing with them anyway, because of the dodge penalty) at least let SOMETHING be done about players who are toxic before (and after) the game starts!
P.S.: Bring back the 'Unskilled Player' report as well with a small, but stacking LP penalty for the receiving player. Say, -1 LP on your next game per report. Habitually bad players who get lucky in their games will climb slower, feeders and other griefers will drop faster (reducing the number of ranked games they can effectively ruin above Bronze 5) and, most importantly, good players can directly hit toxic players in their 'bottom line'. Yes- toxic players. If you are bad and refuse to learn, you are as toxic as anyone who is feeding intentionally.