Hey, I just noticed you responded to my Roland = Crimson King idea. Thought I'd elaborate a little. I figure if Roland goes back and meets Stephen King again, he'd find out what's going to happen at the end of the story because the writer finished it. Well, if he figures out that he's trapped by the tower, isn't it likely he'd go crazy and want to knock the damn tower over anyway? Isn't it possible the tower made by the old ones is bad and needs to be destroyed so the real prim tower can heal?
(SPOILER TO THE ENDING, just in case you'd read this first, sai reader)
To me it seems that he is not stuck permanently in the Tower. I think he can change his destiny somehow, and maybe with the horn of Eld he will just do that, and 'move on' to wherever he is supposed to go after the Tower. I really think the Tower is necessary and must be protected. I don't remember well how Roland got the horn, but maybe the Tower gave it to him, because somehow he 'evolved' during the journey we just witnessed and it is some sort of reward for Roland.
One could look at the fight between Roland and the Crimson King as an internal struggle, and I'd say that's a very good and interesting point. It could very well be true.
I think the ending opened a door for all of us, Constant Readers, and each person that goes through that door will se something completely different from the others, because it's a very personal journey, depending on how you perceived the story of Sai King. And isn't it beautiful, really? That's why this is a perfect ending, at least to me.