Dicks are intentionally vague on this point and will stay that way, just interpret them as you will.
Yeah, but with this game, where do you draw the line between "too much" and "too little"?
You've got minutia modifiers for the depth and elasticity of your holes, production regeneration and production quantity for body liquids, the shape of your horns, cum with different flavors, even the ability to bleach your asshole. By that logic, you could also ditch every sub-morph species and stick only to the bigger archetypes; feline, canine, avian, equine, etc, and let your imagination interpret whether you're a caracal or just a simple domestic cat morph, or between a zebra and a Shire. (IMO, I think I would have preferred it this way too. Exception for mythological creatures, which deserve a category of their own.)
The point is, with the (vanilla) game trying to be incredibly in-depth in some areas, with a ton of customization options (including spawn rates and gameplay sliders), where do you draw the line?