I think the viewpoints aren't really supporting the mages or the templars, per say, given that the mages have approximately zilch idea of how to run a war and the templars are high on Red Lyrium. The standpoints are probably more 'pro-Circle/status quo' and 'anti-Circle', with some variation between people. With that in mind;
Cassandra: Status Quo. She wants everything to go back to how it was before. When things made sense. Unfortunately, that's not likely to happen, like, ever.
Vivienne: Pro-Circle. She wants the closed Circles back, with nice thick stone walls to protect mages from idiots and idiots from pissed off mages. She had a good life in the existing system.
Varric: Status Quo, I think. He's probably fed up with all the idiots and wants to smack their heads together until they see sense.
Blackwall: Neutral. The rifts are the problem, and Blackwall probably doesn't even concern himself all that much with who wins the war, because in the interim, a lot of innocent people are being killed by both sides?
Sera: I'm inclined to say she's Anti-Circle. If she looks out for the little guy, who's the littler guy than the one who's been systematically locked up for 800 years? She sees who's in front of her, and she'll probably see the person in the mage before she ever considers the explosions.
Iron Bull: Pro-Circle, maybe even harsher. He's still Qunari in morality, I'm guessing, even if he doesn't really behave like one. Mages are dangerous, and this just proves it.
Solas: Anti-Circle. If anyone is for freedom, it's probably our resident fiery apostate.
Cole: Neutral. I think you might have the opportunity to persuade him one way or another.
Dorian: Pro-Circle, with weakened templars. As a Tevinter magister, he sees Circles first as institutes of learning, not prisons. While his dislike for the practices of other magisters might lead him to support templar presence, I'm guessing his belief mages should be in charge is too ingrained to forget.