In regards to the discussions about magic distribution in the party, my personal input on the subject: I would personally go with Dorian as electricity, Vivienne as ice and Solas as fire.
To me, Vivienne is all about focus and poise. I've always associated these traits with ice. Vivienne can be just as brutal as winter, and I love that about her. You have to be careful with her because she doesn't entertain the idea of mercy, should you call her a foe. I also love the idea of her quick-freezing enemies with the flick of a wrist!
Solas is introverted and reserved, but as he's described as "scotch bonnet candies" I imagine he can be quite explosive. Coupled with his self-teaching, I've always seen fire as something quite easy to conjure but extremely difficult to control, which has given him a greater opportunity to temper his spirit. This would show the level of discipline an apostate like Solas would have to exert in order to stay hidden for as long as he has.
As for Dorian, I love the idea of him primarily using electricity spells because he's been fascinated by them from a young age. There's something primal and wild in that sort of magic, and it's like his way of letting loose in a manner acceptable to his peers while he's studying. It is an extension of his divorce from the rigid traditions of Tevinter - he simply cannot be held by a society that condemns him, just as lightning cannot fully be mastered by a mage.
...And now everyone knows I spend waaay too much time considering how I spec my mages.