I think ranking up/down would probably take more time, not less, under an impartial matchmaking system.
But for all this talk about win rates not being the best gauge of player skill, the SR system is essentially based on win/loss. Players do not move up in the SR system without winning. They do not move down without losing. All the more reason why the outcome of matches is important. And that is why it’s a problem when we face an uneven playing field, rigged by the workings of big data (MMR) that we do not understand.
When matches are handicapped with MMR, we cannot trust the win/lose result of our matches as proof of our skill. That is why the SR system doesn’t work. As Kapoof commented recently:
So yeah, well put. Getting gold medals in one match makes you lightening rod for MMR to strike in the next, by putting you on a team with the worst 5 out of 11 players available. That is what typically happens in solo queue, and in group play the matchmaking system has other ways of tilting the scales.