Thinking back, the Zoan Devil Fruits reminded me of a somewhat good children's bookseries I used to read back in the day. Digging up various copies of Animorphs, I believe I have an assertion to make:
"Is Lucci's most powerful form not his beast-leopard transformation, but his purely leopard form?"
I say this because the Zoan fruits are pretty weak if all they offer is the standard beast-man form transformation; aside from Chopper, whom apparently is smarter in his "beast-man" form, there only appears to be an increase of size and strength for Jyabura and Kaku. I could compare this transformation to that of an Oozaru or perhaps a Kaio-Kan; all it serves as is a "power-up" skill no different from any other beefy boosting methods.
However, the beast form intrigues me; Lucci already demonstrated his beast-man form, and I think it would be a tad boring if all three of the most powerful CP9 agents basically fought in the same way, even with different "masteries" of techniques among the six forms. Lucci, apparently a combat expert, would be foolish not to train his purely beast form; indeed, it offers several advantages over the man-beast form.
*Increased speed (four legs).
*Claws (which Luffy cannot simply bounce back),
*A tail (Shigan, anyone?)
The beast form offers a large number of possibilites for a Rokushiki users, much more than in the man-beast form which simply offers an extension of those abilities. Thoughts?