Regarding Riya (since it's coming up as topic recently), I wish there was a more of a open and honest path for that route. (I haven't played in a while so this might have changed from the near-cheating orbit for Riya to be interested without spurning this character away in the game.) While I have nothing against others having the male MC be a beta or the female MC being reduced to a glorified onahole, I prefer the preeminent couple in games like these to have more of a stag & vixen dynamic in a fully trusting and loving relationship.
To elaborate without kinkshaming as it's just another respective perspective, I dislike pathetic loser-type male MCs and braindead bimbo-esque female MCs. Again, I have nothing against those that do as we all like what we like and don't like. Anyway I would much rather see a confident, strong-willed male MC with a playful, intelligent female MC being a power couple that they know they are. And it's by their choice that allows others to join in on their sexcapades regardless of how the couple first became interested in the world of sharing.
Seeing how the female MC is enjoying herself with others with their partner's knowledge and permission (for the non-cheating routes), I'd like to see more of that on the other side too. This couple that is devoted to one another in their partners could also have the other half of their equation being the one shared as well. Going back to Riya, Nat could be the one that shares Ethan with her (with or without Riya first knowing about it). Nat could even experience some cuckqueaning as well and could be there watching Ethan with Riya, or even directing them when everyone's relationships evolves to that point. There's no reason something like that couldn't happen, right? Nat already knows there are people like Riya that could be on the prowl of someone as awesome as her chosen partner Ethan after all when he was looking to land the office job in this game. I don't see why the couple can't explore and have an honest conversation about Riya (or with her) like they've done for Nat's partners.
Just tossing a nod towards a more dominant Ethan playstyle with a fun-loving wife in a non-cheating-exclusive route involving Riya. ^^