I'm not that far in to make a sound judgement, but looks like the same 'ole Deep Roads to me. Very little banter from your companions. The enemies don't really fight with special skills or techniques, and they don't seem difficult so far. They gave them a bigger health pool and it becomes tedious to take them down.
Edit: Also, everytime I see a genlock, I think of this:
Lol, I can see that, though I actually liked the genlocks. And it was pretty cool to see the ogres again. I thought they did a good job on all the dark spawn models in this one. So far though I am of mixed feelings with it. Like you say it doesn't taken any special skill to take these enemies down they just have ridiculous amounts of health. And then later on you fight enemies that are resistant and immune to almost everything.
I like the banter between the two new dwarven characters, and I like the stories that Renn will tell, but there is very, very little banter between your companions at all. So as for multiple playthroughs, I am not much seeing the point. The story thus far is...underwhelming. It feels more like hack and slash. I have not reached the end yet but...I am not expecting this big secret that they say will shock the foundations of Thedas to be all that brilliant. I might be wrong but...I have learned to temper enthusiasm with Dragon Age.
There are some seriously awesome visuals though in The Descent, as well as some pretty neat new armors and weapons.