Just one problem.

Rating: 9/10 (12 June 2015)

Almost all of Stephen King's novels end badly for one or more of the protagonists. For example, in "Cujo," the boy dies. However, Hollywood has a problem with kids dying horribly and re-did the ending of the movie version, allowing the boy to make a miraculous recovery.
This movie remained true to the novel in that the protagonist (John Coffey) dies. Perhaps King insisted that the movie remain true to the novel because King is anti-death-penalty - and wanted the novel & movie to make a "statement" in that regard - that some innocent people get executed.
In any event, when Coffey was explaining to Paul "why" he wanted to die, he said, "It's the way things are all over the world."
(possible spoiler warning) Knowing what they knew, Paul, Brutal & Harry could have provided Coffey with a far better outcome. First, and this wouldn't take much convincing, they'd need to convince Coffey that it wasn't the way things were "all" over the world - that there were places where he could find peace and contentment. Then, all they'd have to do is sign a statement to the effect that they witnessed Wild Bill's deathbed confession ... admitting he'd committed the crime John Coffey was accused of. A deathbed confession witnessed by three people of good reputation is almost never disregarded by a court of law. With that signed statement given to the prosecutor & Coffey's public defender, a new trial would have been a given ... if it even needed to come to trial.
Afterward, Paul could have found a job for John doing manual labor (for room/board only) in, for example, a Buddhist monastery - a place where John would be surrounded with peace and contentment for the rest of his life.
I can see only one possible negative ... involving the farmer and his wife. Knowing that it was Wild Bill who did the deed, they'd both realize they'd "hired" the man who killed their daughters - and it might put a strain on their marriage that couldn't be overcome. But, heck, the truth would set them free.
So, I give the movie an overall 9 rating ... taking away 1 point for John Coffey's needless death.