Has anyone considered modding the nipples? Like erect nipples or pierced? Maybe puffy nipples? So many things and it might be easier for those who are just starting to mod. Or am I wrong?

I doubt it so far as modelling has only recently become a thing.

Experience says there's probably 2 option's here:
The first is the more simple, modification's to the current model.

The better/harder option is "attachment's"
A mod that allow for body attachment's. I'm not sure if it is possible but if it is it could have multiple uses.
There's allot of things you could attach to the body but its all guess work from me, I have very little experience in modding.

I have high hopes for this game and it's mod-ability... I might even start modding it myself.