The ranking system as it is, is pretty good but has two major flaws.

First of all: The matches you are thrown into, aren't based of your current rank, they are based on the hidden MMR. This can be very confusing and frustrating. Of course the game is developed in a way that the hidden MMR and your rank try to find each other, but this doesn't always work well, especially when you haven't played for a few months. I for example was in gold, and only played in full high plat-diamond lobby. And when playing with and against diamonds, and being able to keep up with them, it isn't fair to be two ranks below them. If you are a gold player, you should play against gold players, if you are a diamond player you should play againts diamonds.

The second problem is similiar: Currently you can not queue with a diamond 3 player, if you are diamond 2 or below, of course you can play with 5 people and get reduced points. This in itself is anoying, but not a problem. What doesn't make sense is, that when you are diamond 2, you often play with and against immortals, you wouldn't even be able to queue up with. I think it would make much more sense, if the strict queue restrictions also applied to everyone on the server, in the case of a diamond 2 player, everyone in the lobby would have to be between platinum 1 and diamond 2. This would of course increase queue time, but it would improve the fairness of matches. I would suggest either increasing the queue restrictions for higher ranks, or also implementing the restrictions for actual random matches.

Let me know what ya'll think about this!