Zoro protected Hiyori because she's important to Momo. It has nothing to do with his own personal feelings.
I never said I wanted her in Wano. I said if Smoker is coming, she is too. Also, if Marines have a place in the arc, then it's reasonable to suspect they will do something drastic that doesn't align with Smoker or Tashigi's justice. You know, the story arc they've had since Alabasta?
Zoro x Tashigi and her geeking out about the meitos is but a bonus. This isn't even mentioning her possible ties to the Shimotsuki given all the hints concerning Koshiro and Kuina. For friggin sakes, her sword is named after the autumn. The Shimotsuki resided in Hakumai, the autumn region of Wano.