Well, War Cleric is her only class with axes, so every other class would ignore her axe rank. If you want her to keep her Bolt Axes, you're going to have her stay as a War Cleric. Once she hits level 20 though, she can just 'reclass' back into a War Cleric. Personally though, I'd recommend Sage because she would keep her high magic and staves, and she gets Tomefaire through that way, and most of her other classes use tomes. The loss of power from no Bolt Axe wouldn't be that big, and once she gets Tomefaire, the powerful tomes like Thoron and Bolganone would do more damage than the Bolt Axe, and it would help with her staves as long as she has a tome equipped.