Okay - might as well pitch my two cents and careful, this is a long one:
Features? Actually I was about to say that there aren't any - but while writing an idea as something that could be added/updated, I decided to put it in the features list as it would be a bit of a big expansion to the game:
Random interactions between the characters. Right now it feels more like every character is living in a vacuum only consisting of themselves and the MC, except in events. Why not have certain residents walk in on you when you do kinky stuff with a girl in the lobby or when playing with your maids in the kitchen? Or how about them having a conversation, watching TV together (since they seem to grow fond of each other), or maybe, if they have their stats high enough, have them fool around in the shower that you could walk into as well for some nice extra juicy time. It seems like they all just stick to their rooms, except for when they are outside for a day for you to fool around with them, or when they head to the shower. Them only ever coming across each other in a couple of events while living in a (relatively small) hotel seems a bit unlikely, even with their schedules.
Favorites and their stories?
Android and Kali pretty much have to share first place for me. Ashley with her natural style and (more or less) normal attitude as shown in the date is a close follow up to that - I'd love to see some expansion in that direction honestly, though I doubt that'll ever happen. For the Android? I'd love to see her background elaborated more: The Grandfathers' intention as to why he built her the way she is, as to why there are so many errors with her and what not, a more intimate relationship that'd span past the Master/Servant (Or in this case Admin) role. Kali moves in a direction that I honestly could not think of anything even remotely worthwhile to suggest, I'm honestly hyped to see where this is moving.
Next person there'll be mild spoilers, so you've been warned.
Anything else that could be added or tweaked? Oh yeah, I got a couple suggestions there.
For once - the bar: The ROI is absolute garbage and even fully upgraded with advertisements running, you barely make a profit from it. For the amount of work and money that has to be put into it, it's honestly a drop in the ocean and not worth investing in, though it does unlock new fun things to happen.
Traits: While I like the idea of unlocked character traits influencing which options to chose in events, I'd like to see it expand into the scenes as well. New dialogue reflecting that, maybe extra animations reflecting the character being more proficient at the act or enjoying it more (Just as the costumes also happen to change dialogue slightly). On another hand, for a person like me, who loves having all the options available, grinding the stats of all the girls up is an absolute nightmare, especially since you unlock many girls early and after going through just a couple events, you are flat-out bombarded with stats to get up. While it makes sense on the realistic side, grind in games can halt progress for people like me who enjoy maxing out the stats so they have all the options possible and maybe discover new interactions, especially since to max something, you have to do the same action 10x. In some cases I think the game did check for the old number values, though I think that has mostly been fixed - and the maximum rank achievable for any of the action-specific "proficencies" is still 13 which is "Professional" iirc, while the trait regarding that act is unlocked at 10 actions.
-> Long story short, I'd like to see the grind getting reduced a bit on that front, even though it's optional work anyways, and maybe a bit more of an expansion as to how it reflects and expands on the scenes.
So, that's the suggestions that I could think of from the top of my head: It looks like a lot of stuff, some of it would probably require way too much work to actually implement, but hey - even if nothing from that is included, that's not gonna stop me from my $20 pledge to you. But hey, since you asked, I might as well put some thought into it and decided to give out some ideas, never hurts to give out potential inspiration.
However - On that note I'm gonna have to give out a very big "thank you" for you creating such a wonderful game to begin with. I've been watching it since basically version 0.2 and supported shortly after, because I believe this could turn into something really, really awesome and the game kept my spirits up and my nights fulfilled. So honestly, thanks for the work you do and just keep up with it - you've got my support on that.