I do wish Bethesda would drop the idea of having all dialog voice acted. Having key lines and greets, as in Morrowind, was sufficient - and it allowed you to have MUCH more dialog than if you had to voice act every single line. I know you can use silent MP3's to simulate this, but still.
the best part about the way this dialogue system seems to be shaping up is that there's a really good chance it'll actually work magnificently for unvoiced dialogue.
like in Oblivion and Fallout 3 unvoiced dialogue was terrible because everything FROZE AROUND YOU and the face zoomed in and the person talking would do nothing but talk to you. you could have unvoiced dialogue but since everything around you went completely still and without lipsyncing the person just stared at you and it felt really awkward.
Morrowind (and STALKER, actually) cover this really well by just having that huge dialogue window pop up. in Skyrim, NPCs will move around a lot more and actually do other things besides just standing there talking to you, and they'll be facing away from you and doing their job and whatever and the world will go on around you. this system would make the "immersion" barrier much less of an issue when coupled with unvoiced dialogue.
if it actually feels as organic as they've described it i can see the potential a lot of really good less generic NPC mods and quest mods and stuff coming out of this.