As a big fan of the books, I enjoyed this as a continuation of the series. If nothing else, it was great seeing Roland do gunslinger things on the big screen.

I just feel this thing was DOA no matter what they did. They couldn't promote it heavily as being a sequel to the books, because that would have turned off anyone who hadn't read the thousands of pages required to be up to speed. Thus, they couldn't fully commit in the movie itself that this was a sequel, but to me at least it pretty clearly was. If they had been able to commit to that, obviously it would have been ever better for the book readers - more backstory about why this version of Roland was broken, more explicit references to the previous quests that failed (including previous version of Jake), etc. If I had no background going in (and thus couldn't comprehend this as a sequel rather than a standalone film) I imagine I would have thought it was pretty lackluster and skeletal.

Maybe Stephen King will be inspired to write one last novel in the series that picks up from this point?

While I agree they couldn't really promote this as a sequel, it likely only turned into a "sequel/new-trip-to-the-tower" once the push behind this thing was abandoned a year or so ago.

This thing felt more to me like a "let's get a competent movie out the door, put a superhero twinge to it since that stuff is big at the box office, and then maybe we can re-visit the franchise later" type movie.

The talk of "development hell" told me that what the initially envisioned isn't near what we got.

I just finished this movie. I enjoyed it. I thought it was pretty original and different.