he was always questioned. Hell people kept saying Fei was better.
Hell there was Talk that Yang had more potential(alas the world may never know).
Basically with Yun he had some stuff with Crazy Frame Advantage or hitboxes, a beastly rushdown offense, and high amount of Mix ups, with the damage to back it up.
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Oh SuperNiceDog's doing it again dude.
SuperNiceDog, you ain't no pimp dude