The ash falling was sort of mentioned in the first book, but later on when there was heavy ashfall and the mist cleared, everyone could see the stars.

And in the third book, Elend could Push on Inquisitor spikes.

Yeah. It would have been good if he'd described the landscape in the beginning with half as much detail as the fight/chase scenes. I found myself skimming over them after a few paragraphs of running, Pushing, Pulling, etc.

I wonder if the messed up world was a half baked idea in the beginning that Sanderson decided to develop.

I thought the change in perception of the Lord Ruler was very good, even if a lot of it did come from the blurbs before the chapters, rather than a more organic development in the story.

But hell, I can complain; I haven't written a damned book