Mage attacks can't be blocked, and after spending some time paying attention to my fights I'm beginning to think they can't be dodged either. In which case both Break runes and Hit Rate runes would be useless on Mage characters like Shayd, Catherine, Mehvidian, or Smoulder.
Since Mages have the most powerful single attacks in the game, and always use a "skill" hit rather than an auto-attack I think the terrible accuracy rate they have naturally is a way to compensate for their massive damage when they do hit.

It's kind of a lazy way to solve a balance issue, but I'm getting the impression that might be the reason they were created that way, and why there is no rune that actually helps them hit their skills more often.