I don't know about the programming side so I will say the models in Daz3D look amazing and I would lean that way. However, when you ask for categories I would suggest animation, customization, and starting with a small project (okay I know that's not a category).
Animation: If you can't do it well then don't do it. However, even little touches of animation - eye blinks, winks, smiles - help to make the game more "real" or "alive" for me.
Customization: I'd love a game where I could choose how I look, barring that let the player choose the MC's name, relationships, etc.
As for starting small it seems there are a lot of overly ambitious games that get abandoned. If you start small with a well written animated game it seems to me a better idea than trying to write an epic immersive game. You can spend a lot of time getting a little bit right instead of a spreading your time too thin.
Anyway as for the "standard" categories I would like to see more games that are less of the standard. Less giant breasted and butted women and more "normal" women. Something that we don't see very often are games where you play from the perspective of the person being pursued and if you do an incest game (since that seems to be the majority of what is out there) it seems fairly rare to see a daughter seduce a parent or a sister corrupt a brother or a mother seduce a son.
Good luck! I look forward to seeing what you come up with.