I think it's just silly, IMO.
The editing on this is just... bad. We've have scenes of the Grand Cleric and the Divine talking, which just gives the whole thing away. Then, there's Cassandra who seems to gain SUPERPOWERS whenever she's duel-wielding 2 large swords but without them, she just a normal human being. Then, she's going back and forth between "I don't like mages" to "Okay, I'll be mindful of mages". When she's telling Galyan to GTFO, it's inconsistent when she just freed him of his binds. It needs to be a progression in one direction, not going back and forth.
As for Cassandra, I think she's just mean. She's just a rather generic tough woman with mage issues and prone to violence. If Bioware's setting her up to be a companion, I'd be off put by her. She has a very narrow view (which I don't believe changes by the movie's end) and is a rather aggressive jerk. To me, Galyen, who's supposed to be her foil, is a much more engaging character in how he still wants to be loyal to the Circle, even after given ample opportunity.
I like the voice actors, and I think Colleen did as best she could trying to hold an Orlesian accent the whole time, but in the end, I think this movie was silly and entertaining in a humorous B-movie way.