I have a bunch of suggestions for future content that I think would be great.
1 For the gallery, are you planning to just let players view stills or will the dialogue be included? Because IMO the dialogue is an important part of a lot of the scenes, so being able to replay the scene with dialogue is key.
2 More of the side characters should be invitable to the studio, especially if Anna has already slept with them, like Liz, Chloe, or Phoenix. If Phoenix becomes invitable, maybe even a 4some with the player, Anna, Charlotte, and Phoenix. Maybe anyone that can come over to the player's house can be invited to the studio.
3 More Zuri. Maybe a questline where she's curious about who you're buying all of those outfits for. Maybe that quest ends with you being able to invite her to the studio. Maybe the same style questline for Miss Zero, as she feels about the same RE: where her interactions end.
4 Speaking of Zuri, any questline where you chose sharing you should be able to pick the stealing scene on repeats. So using the Zuri scene as an example, if you share Zuri with Joey, you should be able to see the animations for the stealing scene as well if you repeat it. Maybe have a dialogue option in her store where you can fuck her in a changing room, with the option to pick between the solo and sharing scene. Same thing for Alice in the club, if you do her minigame again, you should be able to pick if you want to see the solo scene or sharing scene.
5 Speaking of the club, a scene with Alice and Roxy together would be cool.
6 Currently if you share Sam with Ken, it locks you out of sharing Anna with Ken, and vice versa. I just don't think not being able to share both makes much sense from a story or gameplay perspective.
7 Please do something more with the pool girl. Currently she could technically just be removed from the game and it wouldn't change anything as long as "reserve the pool" was still an option. Honestly if "go to the pool ($3000)" was a dialogue option at Ken's house it would be basically the same. Maybe she sees you banging Sam after hours and wants in. She could have Solo and sharing scenes, where the sharing scenes can be the player her and Sam, PC her Ken and Sam, and PC her Ken Adrian and Sam.
8 Just in general fleshing out stories and scenes for characters already in the game feels more important than adding new characters or new areas. There are a few characters that feel like they're forgotten about because their content just stops at points where it feels like there should be obvious follow up. Miss Zero, Zuri, Chloe, Alice and Liz all feel like they were partway through a questline and you moved on to newer content and kind of forgot about them. The secret NPC also feels that way but I feel like the other characters are way more important to add to.