And even then, my version of KH3 isn't just some clone of KH2 since Riku, Aqua, Xion, Kairi, among others weren't playable especially with how I handled their gameplay.
I guess on a basic level yes, but by keeping it consistent, they can iron out small issues with KH2 Sora, and add new stuff in such as new playable characters and new attacks and mobility options for Sora. Devil May Cry 3-5 have similar gameplay elements and simply added new stuff in while keeping the foundation that worked such as Style Switching.