I'm going to be blunt, and I'm sorry about that, but I don't think linking wetness values to lust/libido is a good idea, at least not without an option or something to go back to the old system. Yes it helps with immersion, but for customization OCD freaks like me it only creates headaches. The preference settings for it was a great idea, but it isnt all encompassing for every scene and such, and with only 4 preference options and much more levels of wetness, especially vaginal, that may not be enough.
Also, and this is actually a bit of a legitimate claim I think, with it being linked to libido/lust, won't that make it difficult to establish a "baseline" or whatever for high lust/libido character, since they'll always be gushing like a fountain anyway? Sorry if I'm wrong and I'm just being an idiot with that. Also theres the squirter flag that relies on vaginal wetness, i dont even know how thats being affected.
I know I'm being super nitpicky, and again I'm sorry, but hey, I'm not the first one to do so, so what the hell.