Ultimately, I had a good time, though it took a while for me to climb over that sudden difficulty curve. I appreciated this in the end because it forced me to take a more tactical approach to combat and actually think about the builds I was using and needing to forge the proper equipment. Cold resistance is a must for this DLC!
I enjoyed the story a lot, mostly because I'm a lore fiend, though I feel the Hakkonites were under utilized. They seem to be the ultimate evil bad guys just because the DLC needed an antagonist. I would have enjoyed a little more interaction with them, even if it was only a few lines of dialog. I feel like that final battle in the fortress would have had more of an impact if I had actually gotten to know who I was actually fighting.
But the DLC does a lot of things right, too. The equipment and schematics you can find here are fantastic, way better than anything I had been using up until that point. There were a couple of moments where I found some new weapon/armor schematics and basically said to everyone, "Wait here while I shunpo back to Skyhold to make this really quick." Because the enemies level up with you, by the end of the story I had made a fair amount of progress in terms of levels. I entered at level 20 and left being level 24.
I really enjoyed Harding getting more screen time, because Bioware really didn't do enough with her in the main campaign. In this you really get a good feel for who she is as a character. Meeting the previous Inquisitor was a welcome treat too, he and my Reinard totally bro-ing it up for a few minutes.
Despite minor nitpicks, I really did enjoy myself and don't regret spending the $15 on it. The amount of enjoyment I got exploring the new area was much more satisfying than I thought it would be, thought I'll admit I did get lost quite a few times trying to find my way up the mountains.