You did compare Mozart to King. You said Mozart, one of the most prolific and greatest composers, known for being able to write out full symphonies without revising, known for writing complete masterpieces almost over-night, and meanwhile creating some of the most enduring and inspirational music ever written, is a comparison at how natural King writes dialog. I admit, King doesn't revise his books, but that really comes from being over-confident, money hungry, and lazy, as apposed to being perfect the first time. King's dialog is not the best, nor is it even top 100. The fact that he spits so much of it out is where the comparison to Mozart ends.
His dialog is rubbish. For dialog to be good, one has to both balance revelation through dialog, as seen in the works of Shakespeare, and Ibsen, in addition to believable sound (I.E. people actually would say that, and do talk like that). I don't think King is good at that, nor much else.
Regardless of this nitpick, the fact remains that even King's early work has begun to period-piece-afy before our eyes.

