This is such a basic and obvious solution to one of the longer term problems in the game. Yes its theoretically open to some small amount of abuse. Then again, so is the reporting system and riot loves that, so that doesn't seem like much of an argument against it.
Implementing it is pretty trivial: 4 votes against a player, he's kicked, next person in the queue is inserted and the game continues. I'm not sure it matters if you restart the pick/ban phase or not, but that's pretty easy to try both ways.
By far the most common arguments against I see being brought up are the idea of premades abusing it in which case you don't implement it in modes where premades are possible. I'm not sure why it wouldn't be ranked only anyway. And lets be honest, if you had 4 people in a premade who wanted to hurt you, them votekicking you is probably the least annoying way they could do it.
The other thing is some vague concern about "off meta" special and unique snowflakes. But you know what? This isn't a singleplayer game. You load up a game of skyrim and you can choose any random set of special talents you want and play how you like. But if you're playing on a team, especially in a ranked setting, you owe something to the rest of your team: specifically trying to win. If you can't convince 4 other strangers that whatever you're doing is likely to help win them the game, I don't think the problem is with them or the system being implemented, it's with you.
Its not like this game doesn't have tons of places to play 'off meta' picks. If you want to play ad zac, go play vs bots, or in custom games or normals or whatever.
And just to make the point clearer, being votekicked from a game is not exactly the end of the world. I don't think anyone is suggesting associating a major penalty for it, just drop you out of the queue and maybe prevent re-queuing for a minute or two so you don't get back in the same game. You can join a new game and try to convince those dudes that your ad jungle heimer is the way of the future.
