So I think I have an easy solution to the placement problem that cropped up this preseason.

http://boards.na.leagueoflegends.com/en/c/developer-corner/3m3sPjar-odd-placements-in-flex

For those who don't know placements and the matchmaking algorithm was bugged in preseason and has caused some really strange stuff to happen, like challenger players going 10-0 and getting placed in bronze 5 (yes, confirmed, screen shots posted, this actually happened).

Here's the easy fix Riot: since all this has to do with flex q and it seems it is only affecting flex q as this is the only ranked q up at the moment why don't you just remove the current placement coding, forget the soft reset (which is basically meaningless at this point) and just do a hard reset for all players for flex q MMR and start everyone at 1200. You can do the soft reset as usual for the upcoming season for solo q MMR since that is likely to remain unaffected since the only ladder currently up is flex q. But just go ahead and hard reset everyone now that millions of players have been affected negatively by the bug. This will undo the damage rather quickly, it won't require a downtime event or a massive overhaul of anything, Riot won't have to manually adjust people's MMR, and this will affect every player the same way as opposed to how the bug caused some players in gold to go 0-10 and place in platinum while challengers go 10-0 and get placed in bronze so it means this action would be a relatively fair fix as well.

It's the best solution to the problem, might as just well hard reset everyone for flex q MMR and start everyone from baseline again since y'all screwed this one up so badly Riot.