Does Stephen King write better when he writes regular fiction?

I understand what you are saying, but I think it has more to do with the time that he wrote it. Most of his horror books are from earlier in his career. As it progresses, he changes to a more realistic style with a slight twist of the supernatural. But the books that you mentioned had no elements of the supernatural (except for John Coffey). I think it is more of that element that is swaying your taste. Not just the fact that he writes horror fiction. But hey, to each his own.