DS,
I had some thoughts/feedback:
1) I know Eric isn't popular, but I'm personally looking forward to seeing the control route with him expanded. I think it would be interesting to be able to push Eric into helping you get more from Ann and to convince Ann to knowingly let you do more (maybe as a sex-ed ruse?). Afterwards, it might make for an interesting story arc in then getting rid of him like usual, having Ann push back against your advances again since he's gone, and having you try to assert yourself as her new master. Having to convince her to go along with it, and make her want it based on how she already knows what it's like with you, could be a cool scenario for people that enjoy that part of the game.
2) I'd like to see the Lisa sex-ed route expanded some without Kira. Having Lisa genuinely interested in trying things with Max while being shy about it and working herself up to things was pretty hot, in my opinion. I liked that she was convincing herself to do more with you (like playing with herself at night while you watched). I think it'd be worthwhile to have them do more on their own, even if you haven't talked to Kira about giving her lessons. And Lisa initiating some more.
3) Definitely would be interested in seeing more expansion upon some of the smaller scenarios you created in the game. Spanking Alice was a really good one, especially when you get to the point of complimenting her and she seems like she really liked it, which made me want to see that keep growing over time - maybe her starting to get a little excited when you suggest the spanking and taunting you to see if she can get you to go a little further with the punishment (then building it up little by little). Or when you're watching movies with Ann (not the porn ones used to advance the new career plot, the regular ones) - I would love to see the ability to build up a relationship with her through the events, since they seem like an excellent bonding moment that goes mostly unused aside from fulfilling grind needs. There are a lot of little moments like this that have the potential to build things up in a way that's based on desire instead of the manipulation used in so many of the plot lines. (That's not to say that I don't want those other plot lines - just that I happen to also like mutual attraction between characters quite a bit and want to see more of it.)
4) Would like to see more store items to affect gameplay. It just feels very empty after you get past certain events, and I think being able to do more with the money you get in-game would be nice. Maybe some wine you can give to Alice (where she knows you're giving her wine) in events after you've given her chocolates a few times, to get more of a rise out of her. Maybe some massage oils to use on Ann to alter her mood a little when you're massaging her. Some toys to use on Alice during her cam show would be cool, after she's already letting you fuck her for it - it would probably be an excuse to have her let loose some more in enjoying the pleasure.
5) I think if you're going to do some additional romantic options - Kira is a good choice. Since she's spent so much time focused on sex and has basically blown off romance completely the entire time, catching her off guard and creating actual romantic feelings in her would probably make for a solid twist on her story that couldn't be had from any of the other girls. Would require more effort to make it believable, though, so I get why you might not want to go that route.
6) I think too many of the 'opportunities' have been left dead-ended. There are lots of loosely intertwined storylines and they're not really getting meaningful conclusions. Seeing more progress on these stagnant pieces would be good, before they lose too much appeal from sitting around so long and being played so many times.
7) I hope there will be more yoga stuff with Ann to come (including going 'beyond' doing yoga in that scene).
There's other stuff I've thought about, but this is already quite a bit of text, so I'll leave it there.
Hopefully it's helfpul in some respect.