No Mutants Allowed

I didn't doubt that. And that's my main worry.

For me, the question 'Why do you want to climb that mountain' was always much more important.
What's a big open world worth, if it's just boring filler? See Skyrim or Fallout 4.

Well you do to find sweet new dungeons or parts of the overworld(s) with unique concepts, items and bosses to see, and of course with the ultimate purpose of building up to the end.
But I hear that there are like, 5 dungeons?