I really like this game in that it is a sandbox game that truly plays as one. A lot of sandbox games on this site very much play as visual novels with a lot of randomly checking places to try to trigger the next scene.
But I have some feedback that I think could improve the game.
For me, there were two major negatives.
1.) The inventory management is pretty bad.
I spent a lot of gameplay time getting rid of conversation topics I did not need or want, and it wasn't in any way fun or enjoyable. I think the whole way that it is managed could use some reworking, however I also have some suggestions for smaller changes that should help a bit and hopefully might not be too hard to implement.
a.) Allow for a whole stack to be trashed or burned for exp
b.) Allow a topic to be set as a banned topic that will not be added to your conversation inventory any more until the ban is undone.
One or both of those changes would reduce how much time is spent just going into your conversation inventory to trash unwanted topics.
2.) The one everyone brings up. The excessive grind.
Figuring out how to use the various options get the right conversation topics or events to increase exp for the interest you need to 100% is interesting and fun. Doing it 30-50 times after you have figured it out is not.
It also has a strange curve. Towards the later part of the game it is not nearly as bad as you are getting 8-10 exp per interaction, have a lot more tools for getting conversation topics, and you have probably already raised many interests partly or all the way to 100% already from previous interactions.
So you may only need to grind 1 or 2 interests to get to the next archetype, and you can probably do each one with 10-15 interactions each. Which is still a little grindy for my tastes, but not excessively so.
Contrast that to when you are first starting out where each interaction may be earning as little as 2 exp a go, you will likely need to grind out 2 or more conversation topics from other characters or events to even be able to have a conversation to raise it, and you have to dedicate more time to taking care of your meters so you don't run out.
As a result it takes significantly more time to get 100% in the interests needed to advance archetypes in the early game since they always require 100 exp to 100%. And the early game archetypes have nowhere near as much erotic content.
So you get a curve where you spend much of (if not most) of the game grinding through the first few archetypes with little erotic content, but then move through the later more rewarding archetypes much more rapidly.
It is a situation I don't find ideal. That curve should be reversed. You should be able to get through the first few less rewarding (the reward being erotic content in this case) archetypes easier and as you acquire more tools for acquiring the topics you need, it should become more challenging to get to the later archetypes.
I don't really have any specific suggestions for improving this, but I do think it is a major point of detraction for this game. I will certainly use a mod/cheat that increases the rate of exp gain when I replay it for future updates.
The grind for your personal skills is also excessive, but it does have the correct curve. It is easier for the first level, and gets progressively harder, but more rewarding, for levels 2 and 3. Just increasing the rate of exp gain in general is the only improvement that is really needed there, IMO.
One other random thing I think would improve the game. Raising interests and skills, especially ones that are more sexual in nature or important, should be less based on spamming specific easy to perform actions and easy to acquire conversation topics.
Take incest for example. When I played through I raised my own skill level by using the watch incest porn action over and over and over and over again, and then raised the female character's interests in it by using the permanent incest topic from the skill to talk to them about it over and over and over.
I feel it would have been more interesting if I raised my skill in it more from the flirty/lewd events with family members, and also if that was the primary way I raised their interest in the topic. For that reason, I don't think the incest skill should provide the permanent incest conversation topic, and I don't think it should be as easy/guaranteed to generate an incest conversation topic from simple easy to access actions like watching porn. You still may be able to sometimes, but it shouldn't be guaranteed.
I also think the events and conversation topics that generate exp for it should reduce how much exp they provide for repeating them. The first few times you get an event or use a conversation topic you get the full exp for it (for yourself and the other character if relevant) but it should reduce how much exp is gained from it, or maybe even stop providing it at all, as you repeat it.
That way you would be encouraged to try to seek out and find the different events and or conversation topics that can provide exp for it, rather than spamming a simple action over and over.
Something similar could be done for other very important topics and skills. Really, any time players are just doing the same simple thing over and over and over is something that should be looked at for ways to diversify how players will accomplish that.
TL;DR: I think overall reducing the grind and inventory management time, while also forcing players to find different ways to raise exp for their skills and other character's interests would make the game more fun and engaging.