I don't think that's a very smart solution. I think the smarter solution would be to add a "vote to kick" option in the que. This way, trolls are punished, not the players.

If you go into ranked que alone, you would need 4 votes to kick the troll out. Of course, the troll is then put on a 30 minute waiting period, increasing every time he is kicked out, 30, 1 hr, 1 1/2 hr and so forth.

If you go into ranked duo que, and you are the target to be voted out, your duo partner won't even get to vote, to deal with duo trolls.

This system seems fair to me anyways, and I don't think you can just get 3 other random people to gang up on one guy you never met before, suggesting that would get you kicked out. This seems like a very fair system to me, and it should be added to the game so it makes ranked games smoother and almost troll-free, of course this feature should NOT be added to normal ques. Who cares about normal ques? normal que is their to mess around not following the meta.

The elo-loss for dodging is a excellent idea.
A better solution for the players tanking elo is to suspend them after leaving 3 queues. Harsh but this will stop players from tanking elo. However if there was a report button on the champion selection screen, and 3 or more people report 1 person for trolling, then that troll and any people he duo'ed with will be put on a 30 minutes wait. This also applies the 3-leave suspend rule. Riot should make special suspensions for these such as 12-hours, 2 days or 5 days.
Another method is that riot should include is showing the players' current elo and their elo 15 changes ago(their elo before it the most recent 15 times it changed). This way if there is a significant difference (around 200-300 elo+) players can report another player for tanking elo if they went something like 20/1. Then in the Tribunal is should show the most recent 15 changes to that reported player's elo. If it decreased by increments of 10 the majority of the time then the player should be found guilty.
Riot may start changes immediately or never look at this thread but this is my personal opinion

Imho a simple increase in the penalty would likely stop these issues. Instead of 30 minutes, make it an hour for the first. If they do it again that day make it 24 hours fir ranked queues and an hour for normals.

Sure its still just time, but at least it carrys more weight.

If you really want to get creative, you could say that each dodge after the first within x days gives you an hour wait + no elo gain on your next win. You dont go down but you cant go up until youve cleared those debts. This way you cant cherry pick. You can still avoid a big loss if needed and if you need to twice, you just have to make up for it.