If Kaido was a DnD class, he would be a Barbarian character.
Usually very straightforward. It's all about hitting things and hitting them hard. Being the strongest, strength is what defines his morals, etc, etc. A stereotypical warrior-esque approach.
For that, I think Kaido did his job very well. He's indeed worth of being known as the World's Strongest Creature.
I think trying to make some flashback to try and make him more "complex" did not work at all. In the end, Kaido is bad because he's bad. He decided to enslave a whole country for decades because reasons. I think that having the JoyBoy "reveal" through Kaido being the villain to trigger it was really poor. Instead of a lore perspective, JoyBoy ended up being a power up one, and I think that's lame as fuck.
His fruit was good. Not very well explored. I think Oda did a bad job at mixing some "dragon stuff" with Kaido's fighting style. We saw him shooting some beam while in hybrid, but Queen shoots beams as well, so that's not really something "unique". Creating those cataclysms he creates while in Dragon form, but in Hybrid, or creating a flaming cloud to fly around the battlefield like BM used Zeus, etc, could have done the trick. Something more than "I swing my club, but now I have scales and a tail".
Overall, post TS I think both Kaido and Big Mom ended up surpassing the expectations I had for them ever since we were first told about the Yonkos. i've always considered them "filler" Yonkos, so I was glad I could enjoy them to some extent.
I think Wano has A LOT of problems, but I definitely wouldn't put Kaido himself anywhere at the top of that list.
A solid villain for One Piece standards.
7.5/10