I always viewed it as an excellent idea poorly implemented.
While it worked great for keeping people who tilt in to intentionally feeding and AFKing out of ranked, it seemed like flamers were always prioritized over them. To me, that's silly, because just because someone flamed doesn't mean that they're going to troll because they got a chat ban. In fact, I categorize flamers in to one of two groups. There's the guy who doesn't care and is a borderline troll to begin with and will flame for a reaction while doing asinine things in game or will flame while "teaching you a lesson with a loss" and then there's the guy who flames because he's passionate about the game. There's never an excuse for flaming your team, but the guy who flames because he's angry that his team isn't listening while he wants to win and the guy who flames because he wants to make people upset are two totally different people, and treating them the same way creates more problems.
Maybe this is an unpopular opinion, but I would have liked to see ranked bans target unintentionally negative players, as well, with no other penalty to their account. By that I mean, you lose 3 games in a row while going -10 in each, you get handed a 1-3 game ranked ban to cool off. Something along those lines could keep tilters (who are a massive problem) on their toes and to teach them their limits.
tl;dr: Ranked bans for trolls and tilters, not for flamers.
