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 RR system seems to care mostly about kills, I often play smokes and there is absolutely no reward for playing controllers. I may win but i get like +12 while the duelist get +25. its such a weird system