If you are not interested in doing something its all good - anything I suggest is merely stuff that I think might be a good match for the game - I am not you so I don't know what you dislike and I'm not a developer so there is bound to be a couple of overly complex suggestions occasionally.
Re: Nipples for flat chest - it's hidden behind the fur for furry characters.
Is it meant to be hidden on human characters, regardless of gender ? ... If not then I may have found a bug.
On the subject of nipples perhaps an option to be added to always show / always hide / hide if furry / hide if non furry / [other choices here] could be added.
Pretty much just a visual toggle similar to how pubic hair is handled - a few different visual options to chose from.
And another one while I'm thinking about it:
Have you considered name 'cheats' that automatically generate a visually unique character ?
Something like naming the player character 'Silverscale' generates a randomized character with a silver, scale-like pattern on the characters skin as an example.