I shared many of those criticisms, especially the convenient way the magical doorway or power the characters needed just so happened to materialize at the opportune moment.

Speaking of villains not living up to their potential, I found Flagg/Walter's death to be even more anticlimactic than the way the Crimson King was erased from the story, so to speak.

One criticism that I would add is the way King seemed to change fundamental character traits in midstream to suit the story, particularly with the start of book 5 (perhaps understandably, given what he had gone through in the interim and his desire to wrap things up). Before Wolves, it was clearly Eddie, not Jake, who had the Touch. I'm still not entirely clear on whether Farson and Flagg/Walter were the same person, and I'm not sure King was either.

With all that being said, the second and fourth books, and to a lesser degree the seventh, captivated me in a major way. Let's hope the big and small-screen adaptations don't butcher the books too much.