Again, it loops back to storytelling. As another user (I forget who) posted elsewhere, the whole Niao Sun twist / reveal would've carried more weight if 1) Ryo even knew she existed, say by a character at least mentioning her name once in Niaowu and 2) 'Niao Sun in disguise' did anything to win Ryo's confidence instead of just being there.
There was actually A TON of potential there for a big reveal - either by a confidence trick, like luring Ryo into a trap by preying on his instincts to "act without hesitation, to do what is right" (YI), or alternatively as others have said, by an attempted seduction (which, knowing Ryo, would be unsuccessful but very interesting).
Or anything really. There was massive scope for a payoff to Niao Sun's reveal.