Well, I think there's several reasons why:
1) She's recruited late in the game and also one of the last mages to be recruited.
Obviously we can't have all units with us and since we get other mages so early on then why waste the time getting her caught up, unless you like her as a character and use her anyway. I've used her in my gameplay and she's alright, I do feel sorry about her though because of the lies she has to go through. :(
2) Her personality.
I'd hate to make it sound like I don't like her at all but her cheery personality seems kind of strange considering she's in a dark organization.
3) Stats.
I don't want to say it but stats truly does affect a character. I mean, if she had the stats that rivals Hector, then everyone will use her. You can have the most likable character ever but if their stats are extremely low or that it takes a lot of effort, then players tend to dismiss them.
That's my guess though. I Tend to side personalities over stats. :I
