PROBLEM: Dwarves are immune to magic in Thedas. They can't break through the veil and Lyrium has no effect on them.
Yes, i know, there's sandal but it's still unclear what's his ability - some guess he uses runes to attack.
I think for now it would just add more questions and seem weird, if the developrs broke the rules of the world they created just because some wished for it.
It's been confirmed that, after going topside long enough, a Dwarf will lose his immunity to magic. This is because they are no longer constantly exposed to the lyrium-laced walls of the dwarven thaigs.
One interesting thing to note; does this mean that dwarves and elves will go insane from exposure the longer they spend in the Deep Roads?
Doesn't seem to work that way from what we've seen, but it would be a nice touch considering how the length of the Deep Roads drives most people bananas.
On a more troubling note, this probably means that the Cadash inquisitor will not have the resistance to magic that Aeducan and Brosca wardens did, due to likely being the first playable surface dwarf. They are going to be surface dwarves, right?