Gandalf And Bilbo

That's probably as close to the truth as Tolkien would admit to. Gandalf certainly wasn't spot on in any ability to foresee events. In many cases it appeared that he had only "vague" ideas as to what was going to happen. Which is good for character development. The wizard does have powers of a sort, but is also anchored with inabilites as well. Otherwise, he would simply solve the problems himself and there would be no story.