At the end of every week you can pick an activity, these are mostly used to change your character's mood because what mood she's in determines how well she can learn various skills and skills determine a hell of a lot.
Sometimes you can also talk to someone.
Here's the problem: You can only talk to someone if there's PLOT reasons for the conversation. There are, I think, two exceptions. You can tell your cousin that you like seeing her, you can tell your father that you love him. (One time each.) Other than that if the option exists to talk to someone you had better talk to someone because PLOT. You might choose the wrong person, but these things happen.
That's... kind of annoying. It would be nice if you could talk to people because you wanted to and recognizing that PLOT meant you should talk to someone was on the player's shoulders rather than directly indicated because that's the only reason you're allowed to talk.
There are two reasons I see this as a problem. One is that when social interactions are only for PLOT and you have a reminder of that 40 times in a given play-through it's sort of like the game screaming, "I'm a game!" You'll never forget a game is a game, but having it scream that it's a game is usually undesirable.
The game does a pretty good job of not screaming that out in other areas. For example it'll never say, "Even though you still have stuff left that you could learn in this skill, there's no game mechanics left that checks it so you can't take these classes." Actually, even after you have nothing left to learn it will still let you take classes, they just accomplish nothing.
When your decisions change the story it does so in generally natural and unobtrusive ways so it feels more like plot than PLOT.
It would be nice if the weekend conversations kept that up.
The other reason is that from a purely enjoying the game and having fun perspective. Being able to talk to the people in the castle, regardless of whether or not there was PLOT to the conversations, could give you other perspectives, interesting insights, and so forth. I'm not suggesting game changing insights, though if any naturally arose from being able to talk to people they should be there and moreover they should have already been there.
From week two onward, if you let her stay, Juliana is always at the castle. Alice is always at the castle regardless. So is your father. So is Selene (priestess who becomes important in some circumstances.) Under certain circumstances Briony is at the castle for at least one weekend, maybe two (not going to check right now)
These are people it should be possible to talk to at any time they're there. Even when doing such a thing will accomplish nothing game mechanics wise.
It would give the feeling that people exist independently of plot, which is important, it would give something else to enjoy, and it would change the weekend conversation mechanic from, "I can talk to someone, I guess I should or else suffer consequences/put the plot on hold," to, "Is there anyone I want to talk to, because if I do then I totally can."
I mentioned that if you try to keep taking classes in a subject after you learned everything on the topic you can but it accomplishes nothing. This is another area where flavor text would have been nice. Rather than learning more academically you hang out with your teacher and talk about the subject because you have an interest in it beyond, "I must max out this skill."
It'd be somewhat more satisfying than the "Learned nothing; you have nothing left to learn" that you do currently get.
Plus it gives the mechanic of interest versus usefulness. If it's not increasing your stats then there's nothing useful about taking a class, but maybe you're just interested in it. So you choose between, "Upping my stats in X would be helpful, but I really like the flavor text they're giving me in class Y that's maxed out," which is a legitimate game mechanic.
But that's much more of a, "How I would handle this," than, "This should have been better," thing. The weekend conversation mechanic should have been better. Going to useless classes giving you nothing more than, "You learn nothing, you have nothing more to learn," is a completely valid choice. Not one I would have made, but completely valid.