What makes this more tsundere than any other Asuka?

Nothing in particular, it's just a common tagging misunderstanding.

Tramales, just because a character is known to be tsundere doesn't mean all posts with them need to be tagged tsundere - only use the tag when the picture depicts them being as such.

This is a plugsuit, but it seems to be in the form of a china_dress with her hair attachments as buns... worth a tag?