by far my favorite Steven King books. I think the casting is great... I didn't picture the gunslinger as a black guy but now that they have Idris cast as the gunslinger it seems perfect. The man in black was always kind of a hollow cheek pasty white guy that has a slow talking greasy used car salesman/grim reaper feel to him and I think McConaughey will pull that off nicely.
I always pictured him as a white guy too but only because i am white lol. Im sure readers of all races pictured their protagonist as their own race. that old philosopher xenophanes said it well lol Spoiler: Xenophanes Idris elba is gonna do amazing!