One thing that is my personal preference is when strong willed and proudful characters, like Mia, stay strong willed and proudful throughout NTR, instead of becoming mindbroken, blushing mess.
Background art of NTR route, when you are choosing NTR/NTS, is perfect representation of it. So, if few routes/events let her stay strong willed, like doing it for MCs sake for example, or for the certain objective, instead of pleasure, it will be perfect. (she get's blackmailed, or want's something from some scum, and the price is obvious, she'd rather kill them, but can't and has to comply)
If few events/routes kept her like that, I'll be over the moon. Again, this is my suggestion, I love what you are doing so far, and I love not knowing what is next, so just follow your vision and all will be good!
I'll be replaying the whole game for 0.5 patch just to invest myself again in the whole, wonderfully crafted world, characters and relationships they have.
Also, that cliffhanger was amazing. xD