Originally Posted by
DoctorDodge
Meh, they should've just given it to Christopher Nolan <...>
which made me think of how my three favorite directors of all times would have dealt with the loop:
Hitchcock. [main loop theme: the loop is definitely a
mauvais ton joke, a movie must have an ending that leaves no room for dissatisfaction] Roland is standing at the door, trying to remember the “I’m a Man of Constant Sorrow” tune; the sound of the song played on the piano suddenly comes from behind the door; the door opens and reveals Rosalita playing the piano. She is, of course, Susan, as we could clearly see in his dream where Rosalita complained of having
burned the bread. Now that the Commie (remember “Crimson”?) plot, too intricate for the audience to have followed, has been annihilated, Father Callahan, whose demise had been staged in order to confuse the villains, joins Roland’s and Rosalita’s hands with a wisecrack which will end the movie.
Polanski. [main loop theme: the credited author of the adaptation can stick his loop up his ass] Roland, with bandages on his hands, feet, and nose, crawls up the stairs, and enters a dark room full of small, crooked, irregularly placed mirrors, in which he glimpses reflections of himself, Susan, Eddie, Susannah and everybody else, so distorted that there’s no doubt they had all been plotting against him all the time; the whole movie, in fact, is the story of Roland’s being continuously victimized by the ka-tet and everybody who happened to pass by. He flings himself out the window and lies there in the mud, blood and disgrace, while all other characters walk past and spit on him; the dark tower is substantially darker than ever before.
Kurosawa. [main loop theme: the metaphysics mustn’t be spoonfed to people] The tower burns, the friends fall, the blood flows in dark crimson rivers. Roland, played by Toshiro Mifune, decapitates everything he sees, while Patrick Danville plays the flute, sitting on a heap of mutilated bodies. The Tower collapses, burying everyone who had still survived – rather many, because nobody had been allowed to just up and die under visually lackluster circumstances. Everything is archetypal of everything, so no wonder you can guess the loop and all the rest of it in how Roland casts a last glance upon the dead, and turns to pursue his way further, with a single “Ohayō!”
Conclusion:
In other words, a movie
is the director, if we're talking about the real ones (both directors and movies); if the director is great, it won't be the Stephen King's Dark Tower any longer anyway; but if the director isn't great, why would we need his movie at all?
How would non DT-readers react to the ending of a DT movie ? *SPOILERS*
I'm really impressed--you really know your directors!
I swear, I would walk right out of the theater! 
