I wrote a long draft which got lost somehow. Anyway, I found Long Earth to be disappointing. The book's two main characters "step' or skim over a million worlds, and the plot is just diluted.So many elements are just introduced and not developed at all. We're told at the beginning of the book that Joshua has spent years building stockades like Robinson Crusoe, but are never shown them, or told what happened to his animals when he goes off. So many worlds that are all the same bore the reader as well as Joshua.The main computer/robot character of Lobsang becomes annoying without being affecting. Surviving a trip through vacuum, the (non)relationship of Joshua and Sally. Even a serious theme like a family's choosing to desert a son who can't step with them causes no real angst. The big reveal of what's frightening the trolls, and even a plot ending involving a nuclear explosion have very little tension. It's just a lukewarm book.
Honestly, I think Pratchett's Alzheimer's is catching up with him. He still has more creative ideas than ten other writers put together but now.. he can't carry them out, can't expand or deepen them. This book truly had more of a "tell not show" feel.