I think that makes sense, and I like the reason that vieralynn suggests for it (the life-long exposure to Mist). And yeah, if the source of power is the same, then the method to stop that power should also work, although as you say maybe it's harder, because the source of magic is so much easier to tap.

I'm mostly wondering if Mist monsters could somehow be tainted, in part because of the Mistlands/Blightlands parallel I drew in the first story. But even just now as I'm typing this, I'm having a different thought, that maybe Fran misunderstood what she was sensing in the darkspawn and the Grey Wardens because she didn't have the right frame of reference for it. Hmmmmm.