Theres loads of posts on this topic at the official site with the forums where a lot of people are clearly not happy with the ending.
I could have thought of at leat five different endings that would have brought the dark tower to a close, rather than the cop-out he wrote. It was a load of rubbish (the last few chapters of DT7) and I won’t go into detail as I’ve written pages on the topic.
There is a massive gulf of information that could have been used (from black house / talisman / speedy parker the gunslinger etc), and even though a big final battle with all the characters LOTR style would have been a cliche, it would have suited such a deep and involving set of books.
Oh well, sorry to rant its such a passion of mine (as you can see from my user name) so maybe I should keep to commenting on the CG