What I don't like about Kaija is how she acts in the love route, and outside of it, in the love route she has feelings for the protagonist, but outside that route she doesn't feel anything, if he fell in love with her, it's his problem, it was just work for her.
I think she should have feelings for him, regardless of what the protagonist thinks of her, if he no longer wants anything to do with her, she is the one who lost; but as it is, she just feels bad for deceiving him and nothing more.
What I most want to see is her being jealous seeing the protagonist with Fiona, so she knows what she lost; I also want to see the protagonist becoming very powerful, but refusing to join the Templars, so they too can know what they lost.
I hold a grudge.