That’s not even the biggest issue. Every zoan we have any real data for has three different modes. Their original form, a full transformation into whatever “animal” their zoan represents and a hybrid of “human” and their fruit.

Even other mythical zoans like Marco and Kaido have that.

Luffy is different in that regard. He has elements of his fruits even in base. Is Gear Second supposed to be hybrid? Or Gear Fourth? And is Gear Fifth his full zoan form?

These aren’t huge issues, but they are interesting to think about.