Problem is that’s just a grind fest. Your ranking is mostly determined on just how much you play. Reverse those numbers and it’s more about skill.
Win +3 points, Loss -5 points
As for starting position. Game just tracks those numbers from the start, or once you hit diamond, so you have your win ratio roughly calculated.
But really ELO system is the best, because it basicly does that plus rewards or subtracts extra points based on who you beat/loose to. Win more for beating higher ranked loose more for loosing to lower ranked.
So take that +3 for win, and -5 for loss and now add +1 extra point if you beat someone higher rank then you. -1 point if you beat someone lower. -1 less for loosing to someone better and vice versa. Then their should be an equation to award/subtract extra points if there is a huge difference between your scores. But for the most part it should be working in much small numbers then it currently does.
Currently I think they have some sort of ELO system in place but it is a very poor one, as it is adding and subtracting wayyyyy to many points at a time, and seems to award a lot for win streaks.
Winning/Loosing streaks should have zero effect on amount of points gained. With ELO loosing will suck, but it should not ever drop you more then a rank or two. Where as you need a really good win rate to actually rank up.
Now the time it takes you to grind through diamond gives a fair estimate of your ladder placement. The ladder jumping around won’t be nearly as bad, and rating should more or less be accurate. And you can get there if you grind hard through bad luck, or just do really well with only some games. Your ladder placement should not change drastically wether you play 10 or 100 games, unless you legitimatly and significantly improve your self or fail to adapt to the meta.