Its not that positional ranks are bad per se-- (S9 is S8 but worse)
Positional ranks are bad with duos as an option. Duos should be removed. "Flex" should be the new "friends rank". Even then, flex will be vulnerable.
But first
The matchmaking is the worst its ever been. Its making games not fun. Everyone is pissed, getting reported, trolling, or getting stomped because they'll pit Silver against Plat and Gold against Bronze. I'm about to just let my main decay and not even do placements. Probably gonna just do norms on occasion in this account, if ever, because the matchmaking is bad there too.
I won't buy anything until they decrease trolling and fix their chat ban system--- its made the community worse. Player integrity is so low you could revert to S3 or S4 patch and they'd still be throwing/trolling.
I've seen posts from Diamond Players doing placements for a new account, getting bronze, and struggling to carry through bronze or silver because there's no basic player integrity. Your individual skill as a player doesn't matter if every game boils down to herding cats and who throws last. I don't see the reason to want to increase skill in this kind of environment, because I can't gauge my skill with petty players and tiers that aren't really "divisions".