Kaku did way more than that, and his slashes while in zoan form were still impressive as hell. Reread that fight. Kaku wasn't just throwing techniques into his combat style here and there, it was 100% him personified. This nigga turned into a BOX to launch his slashes, beat Luffy to the punch with winding, used his neck as if he were Jet Gattling, and was developing numerous new techniques during his first fight with it. How does that not stand out as the greatest fruit usage yet when tied to a zoan of all things?So if Kaku could already launch slashes with his body parts using his 6 powers, than why is he good with his fruit to you? If all he did was launch slashes?
It's the same as someone punching you, transforming, and punching you