That picture is both her face as well as how her brain probably looks
It's not really that her eyes are too big though.
I can't really place it, but it feels like they're slightly far apart, as are her eyebrows, by having her nose bridge very much on the wide side.
I've also noticed the lips indeed, but there too, i'm not sure really that they're too thick. I don't think they're that much thicker than any of the other girls or at least not substantially so. Rather, she has an almost unnaturally thin chin and short face, but given how she still has a normal size mouth that only adds to making her lips look bigger.
Though that's just the feeling I'm getting. It could be that I'm entirely wrong on that being the thing wrong with her face. But it's what my feeling tells me when watching her.
I mean, on the one hand I'd say her face is too square, but Brenna's face is far more square shaped I feel but for her it works, so it's not that.
Though not to sh*t on catherine and the dev's work on her too much, but, my other critique about her design would be that while Brenna's clearly Ophelia's child, I really don't see the resemblance to her and Cath at all.
Honestly if I had to guess she's another girls sister in the story I'd sooner say Lucia based on looks.
And as a last pet peeve, before I'm done being negative. I love Brenna, but at times I feel like her tits might be fake?
Though I don't wanna be too negative here as the dev did do a very good job on the character models and they look very good still.
Visually this is definitely one of the better games there are and it definitely stands out.