think the jury is maybe still out on quan. He's almost certainly mid or lower, but he does strike me as complex enough there could be tech. Granted if I were better I'd say he's mostly a knowledge check who's not making top 8.
I'll make a hot take, normally I wait for months B4 making assumptions on tier placements but Quan is special.
He lacks the basic fundamentals to take your turn back, so if your opponent is competent in the matchup and halfway skilled, you are not keeping them out the whole match which is needed vs S Tiers. There are so many F Neutral tools that it's damn near impossible to use zoning alone.
Has good setplay but his mix is fuzzyable. His D1 being 9f is laughable, his S1 is 8f and that means he can't even punish or take his turn vs -7 and -8 moves which is a big deal. Not being able to get the poke out to jail into his also slow jab string is not bueno
He's undeniably low mid tier. Not sure if there is tech that can save him without a overhaul on his pokes.
Annnnd related to that, I still think it's weird seeing Sub anywhere but "can't win a tournament" tier. They made his core bnb easier, which was super nice, and they made his clone "better" but still unusable vs anyone who knows how to punish it on reaction. His tool kit basically didn't change except for when he's fighting you and you have no meter to instantly punish his clone.
Sub struggles in two main areas, a slower mid, and not being able to safely jail from pokes into 12/21 since every string has gaps but F12 which is -7 and punishable by 3 characters and a turn ender into guess vs top tiers.
The second area is everything he does is very punishable:
• divekick is punishable on reaction with UpBlock and backdash wiff punish -21
• slide can't go under most high projectiles because of the force stand for first 3-5 frames
• Clone meterless/1BAR 1 Clone/1BAR 3 Clone/2BAR 3 Clone versions are punishable on reaction by 95% of roster
• Clone Push projectile is punishable by jump in
• Ice Ball is trash 39f startup...
But most importantly he's high risk, low to medium reward on everything. He has to take unfavorable risks to do anything. His HTBs are UpBlock Guardable if overhead first stopping pressure or if low first delay wakeup punishable. Sindel and others are completely safe doing their HTB Vortex and the JIP version is Anti Air punished for no meter.
This is one of the reasons it disgusts me that a player like Ninjakilla was complaining about having to spend a bar with Liu Kang to punish clone a year later, on reaction. While Liu has one of the strongest kits in the game and multiple ways to break clone meterlessly into fly kick and he has meterless punish on clone as well.
Imagine complaining about a tool that stops you from mashing Rushdown mix for 2.5 seconds while Kenshi has you locked down in frametrap for 13+ seconds with time to refresh 15Second timer. Or StormCell Plus frames loop