Um funny how you didn't say to remove elo in general. elo is a system created for a 1v1 game such as chess or card games where the only one responsible for defeat is oneself. This is a team game where anything that could affect your gameplay could happen to any other person on the field thus competition will never be fair unless you are at a live tournament playing on the same lan.

So not only do they need to change the system in which both ranked and non rank divine a players skill level, but I believe it is also unfair that you are restricted to playing with a certain elo level just because you got place in it. When you stated to keep players separate, first of all in ranked you can que up with 1 friend. If you and your one friend make a big enough difference [and you can if both of you can kill 3 people together thus requiring only 2 more team members instead of three] Then viola! you are now not in elo hell. In addition there are things like getting paired with skilled team mates in general where an unskilled person gets carried.

Say you are about to win with two people but your team won't listen to you so you can make the final push and therefore you play a long winded game where 40 mins later you either lose because the enemy team who was less skillful but more team oriented wins or you barely win by some luck. Basically you are saying to only punish dc'ers and not people who cause the game to be hard on others. Yes there are plenty of those people who don't need to dc in order to ruin a good game. If a player plays 3 matches in a row and in a row gets that one person who ruins the game for everyone, how was that even fair? It totally wasn't. Many people can say it has happened to them.

So then how do you fixed ranked in general?
1. Remember that thing that we clicked asking our skill level at the game before play....
Use that to determine how players match up. That way even if people want to play "for fun" in ranked they can play with other people who want to play "for fun" in ranked.
2. If someone dc's doesn't mean they should get banned. Internet isn't a static object that always works/ As a matter of fact there are very few things that are. So then if they have a likelihood to disconnect they should be put in a separate que system with others. This can happen via the leaver buster or a certain amount of leaves. After playing a certain set of games without dc'ing to the point where the game is affected, those players can be reintroduced into the regular que they originally picked.
3.This game should be round robin not elimination. Elimination is that losers play losers and winners play winners. Its a game and that isn't that fun nor does it really determine skill at all as one set of losers might be able to beat a set of winners they were just never paired up. Everyone in each intensity bracket [veteran,rookie,newbie] should be able to play everyone and based on the likelihood of a team winning they are rewarded ranking.

These are just suggestions for ranked, there is far more wrong in this game than ranked imo.