If Oda was going to write Kaido stomping Yamato, I feel like he would have let her solo a Calamity (e.g. Jack) first. Instead he's not even let her use her DF and interrupted all her fights with significant opponents:
- In her 2nd Round with Ulti, Luffy told her to protect Momonosuke.
- When she was about to begin fighting Sasaki, Hacha and Franky showed up.
Despite that, he's built her up as a very formidable combatant:
- All the Tobi Roppo were summoned to capture her.
- Black Maria said that doing so would be difficult
- Her introduction was oneshotting a Tobi Roppo.
- She stalemated G3 Luffy while holding back.
- She oneshot a Number.
- She appears to have a very powerful Devil Fruit given Sasaki's reaction to her tease.
- Ace said that she was too strong to not be a Captain.
- She stalemated Ace.
- She can perfectly execute Kaido's named techniques and uses his exact fighting style.
- Kaido wants to make her the Shogun.
So we have the following:
- Yamato appears to be a very formidable combatant.
- Yamato is using Kaido's fighting style.
- Oda has been hiding Yamato's DF for an epic reveal.
- Oda has prevented Yamato from fighting anyone of note.
- Yamato is going to fight Kaido.
Looking at the above 5 facts, I can't help but expect that she'll get a full length battle against her Father.
#3 and #4 are important to my conclusions. If Oda did not want to give Yamato a decent length battle vs Kaido, then:
- He would have let her fight and defeat another combatant of note.
- He would have revealed her Devil Fruit.
Yamato using Kaido's fighting style and Yamato having a similarly epic Devil Fruit will be flavour for the Father vs Son confrontation we'll get.
She'll not be the one to finally defeat him, but I expect her to do damage and keep him engaged for more than ten minutes.
I also expect a flashback.
If Yamato reveals the ability to clad her attacks in Haoshoku as well, it would strongly reinforce my position.
If she begins a fight with another major character or reveals her DF before her encounter with Kaido, I'll reconsider.