I promised last night to dig out a quote that answers the dual wield question:
From Dutch cover story: Interesting Info http://www.gamesas.com/index.php?/topic/1161723-dutch-cover-story-interesting-info/page__p__17054212__hl__dutch__fromsearch__1#entry17054212
Todd:
So, as of now you CANNOT use fire magic in one hand and frost magic in the other.
My understanding would go further suggesting the player cannot create a spell combining fire and frost, as such I would not be surprised to see all spell creation removed. I mean, to Todd's way of thinking, if you cannot create custom offensive spells why would anyone want to create any other custom spell? The game is all about combat, right?