To be honest, I've been on the verge of dropping her for months now, exactly because I find it hard to actually build meaningful CR for her the way she is now - in the canon, she's very active but that's when she's known as a criminal mastermind, runs a criminal organization and arranges people's murders even from jail. In Kiseki, exactly none of that is possible: she can't kill people because no one stays dead, and she can't really establish a criminal organization because iirc you can't even steal from Kiseki, and trying to outmatch the various magic-possessing characters in the game is stupid and she wouldn't do that. So honestly, I'm kind of stumped as to where to go with her, which is reflected in the plotting post. But the reason I haven't dropped her is because every time I tag with her, I remember how much fun she is and how much I love her, so... yeah, I think you see my problem here, anon.
In any case, I'm really glad for the feedback - I'll try to figure out things for her to do, and if I can't come up with anything, then it might be better to let her go, like you said.