hundredth request to continue NTR content with the Red character or a new one
Pretty sure they just abandoned that.
I do think they could do it "the right way". As a sandbox game, having "heavy NTR" might require some equally heavy coding into every scene. For example, if Red were to be given the chance to "steal" one or more of your girls, they'd have to code all of their content to block, or change scenes with you.
But the way the current content was added is right, imho. His scenes can appear
in addition to the rest of the content. On very specific arcs, such as girl pregnancies, making him a potential father is clever, as it only requires alternative writing in a few scenes to give an different angle to the same content you see when you're the father, meaning girls getting pregnant and kids added to the household.
It would be sad if they'd abandoned all intent of adding more NTR. This game has the potential of hitting a particular spot - one where you have complete control and can indulge in taboo just for kicks. Mentioned before I woudln't mind optional femdom, if well written into the character. Even Anna could roleplay a mistress to you if you asked her, meaning she would come out of her comfort zone to please you, which, in turn, is fitting with her submissive nature. There's a lot that can be done with good writing.
Coming back to the matter at hand, I think there's potential for NTS and even NTR "type C", which is where I think the current content stands (girls are not really into it). Without changing the feel of characters too much - this is a sandbox game, remember, so any radical changes require a lot of coding for character arcs to branch out - there could be scenes where NTR "type C" becomes NTS (girls initially didn't like it or try to resist, but learning later that you don't mind if they enjoy it, they might be open to it next time). This could be a simple "stage 1/stage 2" coding where a scene could play out with the girl resisting or getting into it/teasing you, using the same art.
All of this can be very optional. What I enjoy about sandbox games is the optional nature of much of the content. You only open the arcs that you're interested in.