How perfect is Voynichese?

[Mauro]

Anyway, his knowledge of medicine was impressive, which means he was hardly a dunce.

Even a mediocre artist can take an anatomy book and draw a passable copy of anatomical structures, this doesn't imply any knowledge of medicine. Who knows, maybe imagination was the author's only forte.

And: provided the 'anatomical' drawings are really anatomical and not something else entirely which, in my guess, looks much more probable.