Promo Series Is Flawed

This is not a rant thread about how I can't climb the ladder, or how I'm stuck in "ELO Hell". This is a problem that I think a lot of other players in the community, especially more mature people, might have.

I consistently win games that do not have AFK's/leavers. There's not much to say about "bad teammates" because fact is, I win regardless. When someone is winning this consistently, you would think that a good algorithm would detect this. It would try to get this player out of this division that they clearly don't belong in, for the sake of the players get stomped. However, even at the rate of winning 4:1, it seems you can quickly get stumped by promo games and the general LP system. Point being, even if you were to win 90% of your games, it can still take a ridiculous number of games to climb.

If I remember correctly, I read a post from Riot about their system having been very well designed. Going as far as having math experts reviewing the system. Hopefully this gets attention from a red that can enlighten me on the concept of promo games. They promote you based on a small series of games. As far as I know the system is supposed to determine your ranking based on consistency. Based on performance over the course of many games. This is why, if you truly belong at a higher division, you will climb. So how does it make sense that whether or not you get promoted is based on a tiny sample that may not reflect the overall picture at all? No, I am not saying that it is based entirely on chance. I am saying that it is not based entirely on your performance, despite that the overall ranked system is. Essentially, it feels like the promo series is more of a speed bump than an evaluation confirmation.

TL;DR Even if you win most of your games, it takes too many games to get anywhere. The promo system is out of place in a long-term evaluation system.