The NPCs all share the same AI. There’s no AI difference between Rytlock, Rox, or Magg (CoF) aside from the skills that they use. For story mode dungeons we do beef up the NPCs a bit with their skills since it is supposed to be an easier experience meant to tell a story while providing at least a non trivial encounter for a group of 5 players in a PuG. We are always working on our AI to make them better though.
Easier content appeals to a wider audience. When we released GW2, we got similar feedback about our story dungeons that the MF dungeon is getting now. Nearly everyone could do them, it was easy for a PuG, and people really enjoyed them.
Of course when they stepped into explorable that was a different experience, since we built our explorable dungeons to directly challenge a coordinated 5 man group. Harder content has a less broad appeal initially due to its requirement of player knowledge, skills, gear, etc etc, it is just fundamentally harder and more work. Some people like that, some people don’t, and in MMOs players tend to follow “The path of least resistance” so encouraging them to play the more difficult content has to be matched with higher rewards.
There are always lessons to be learned though. Dungeons are by no means perfect, and getting to see what other teams build always strengthens your design in the end. MF has a great end boss and an interesting army, and lessons can be learned from some of the different things they did. I’d love an explorable version of their dungeon as well