to be fair. the only defensive tool Quan lacked was reliable armor. He had the best backdash, excellent reach including a halfscreen 15f overhead, good movespeed two different projectiles one of which was castable from air and the other one plus on block, and he could summon a bat or a portal to get away with even more and control more space. He could be a brick wall to get in on if the player had solid defensive fundamentals.
In mkx, having the worst armor and wakeup in the game and initially a terrible poke pretty much means you're terrible defensively. How much of the meta revolved around blowing up gaps with armor, often for full combo punish? Up until the end of the life of the game that was huge.
I'm not gonna deny he had great zoning and that he was a good character. But, what does a good OH and mix in general have to do with defense though? I guess you're arguing that the range he had meant he could protect the area in front of him, but he's just not in line with the design of a defense first character. He definitely could zone some characters out, but I don't think that constitutes defense, and definitely not in the sense that most people mean when they talk about defense. Unless you're contention is that effective zoners are defensive by default, which I see to some extent, but I think "zoner" and "defensive wall" are different enough archetypes to warrant distinction. Especially when that zoner has such damaging zoning and mix and offense in general.
A bat was more a tool to keep your turn, extend combos and net damage than a defensive tool imo. It was a good AA and you had to respect it for sure, but again, is that defensive? I don't think so really. Much in the way that batmans trait can be used defensively but it is used more for pressure, combo extension, etc. it still is good to cover unsafe stuff.
TBH I'm not that motivated to debate Quan Chi beyond saying pretty confidently that his identity and design was not defense first.
But this is all moot because Roy Arkon clarified that he was not intending to suggest that Quan Chi was a primarily defensive character.
It is interesting to talk about what tools are offensive and what are defensive, but I think we all pretty much agreed that the nature of fighting games means the line between offense and defense is pretty damn blurry when it comes to what tool is which.
But I think for the most part, people know a defensive character when the see one.
Aquaman (especially pre patch) is a quintessential defensive character to me with the counterzoning, the extremely long range normals, great AA, a trait that drops you out of combos, a playstyle catered to whiff punishing and spacing out normals, etc.
You brought up some good points though, and from full screen and with a life lead, Quan could be played pretty defensively, and his backdash is great, and when his d1 went to what, 6f? That was pretty big.