How awesome would it be to cast spells using voice commands?
Forget about hitting hotkeys, mousing over little icons, or being limited to only a couple shortcut spells... just shout the dang thing! From the trailer, it sounds like the Shouts are in a language of their own, which only adds to the greatness/fun factor! Who needs something as bland as "fireball," "lightning bolt," or (may step on some toes here) "magic missile"?
Sure, a voice command mod would be, say, inconvenient or maybe a little embarrassing in public, but you've gotta admit, someone shouting a made-up language in the middle of a coffee shop would be funny as heck.
Awkwardness aside, I'm sure a voice command mod would add not only to more involved gameplay, but it would also enrich the world of the game. To those who love RPGs for the fact that they can lose themselves in the rich world, a voice command mod would draw them in like a tractor beam snagging the Millennium Falcon.