Most zoans seem to be the strongest in full zoan form. Just look at chopper, who's strongest non-rumble ball form is heavy point.
The only exceptions were CP9 because those guys trained their entire lives in martial arts before getting their fruits. As a result their main style of fighting was useless in animal form.
However, most zoan masters have good mastery in all 3 forms and aren't reliant on hybrid like Lucci, kaku, and jabra.