* There's not much point to it, but I gotta mention parent/child incest. Glad to know Sir Grand Duke Savin isn't opposed to it though! I suggest rounding up the P execs and giving them a good ole spanking. Maybe it'll make us feel better at least...
* I think only one person has mentioned bimbos and bimbofication so far. Shame on you all! Having a super sexy valkyrie lady and a ditzy bimbo in your party is the beeeest! (I have no doubt we'll see some badass warrior princesses so I won't bother mentioning it)
* Addressing the "people want more controll of their character" or wanting to avoid certain types of kinks or scenes, could a tag system be implemented? The little descriptive blurb that goes with the buttons was a fantastic idea (and little warnings like "you'll prolly catch a D in the A doing this, mate"), maybe it can be expanded upon. Say that you tag a scene, or button rather, with the major kinks that the resulting scenes revolve around. Not all the kinks obviously, that list would look like the left side of rule34.xxx. Just the ones that most people are concerned about, like herm (although it's almost always obvious) or domination/submission. For some kinks you might also have a rating to hint at how extreme it gets, for example being submissive but not tied to a medieval torture device and forced to call someone master could be "Sub (lvl2)".
For the sake of sanity and maintaining control of the UI, say that each scene is limited to 5 tags. Perhaps even 5 constant types, such as level of domination and submission, impregnation and kissing (people have some fucked up kinks...)
I have no idea what the engine looks like but I think something like this should also be possible to toggle on and off by the player. Some players like to be surprised after all. Or, taking that concept further, you could flag the kinks you want to be alerted about in the settings so that only they show up and only if they're present. Again, I have no clue what the code looks like but being a dev myself I feel like something like this wouldn't be too rough on time in the long run. It would take a bit to put in place and tweek but once it's there it's mostly a case of making sure the content creators supply their tags (from an approved list supplied by the devs).