I really hope the dev doesnt go the bimbofication/body corruption route like some people want here. It would add literally nothing and actively take away from her design. Shes already thicc, so making her grow literally anywhere else would be comical and just look bad, and bimbo is just...eugh. Whats the point in corruption if her brain literally cant comprehend how far shes fallen? Bimbofication in games like this is just a bad path to go down, moreso if its supposed to be able this connection between two people being tested. If her body and mind literally turn into a different person, its missing the point on what the concept of the game is entirely. Its the same reason that mind/personality-death in TF situations is just a misstep.
Should they be added, I really hope its behind a switch like some content introduced with the latest patch, something that can be easily toggled off.
While personally I think the way its been handled works just fine, with her body language changing the more corrupted she gets, I think that tattoos and maybe hair dye could branch the gap if need be. Hair dye would allow the bimbros to have their fantasy without it explicitly being content in the game, and the tattoos could be a physical representation of the corruption taking place in Colette like the body corruption guys want, as she'd be electing to have them done as oppossed to just magically changing, especially if the tattoos represent things shes done/how far she's fallen rather than just generic succubus tattoos.
Ultimately though I believe in the vision that the creator has, regardless of what's to come. They've done good so far, and the fact that there even are debates on content shows that people are invested in the development!