There is value in being surprised by a story.
I guess that's what it all comes down to, I don't care for surprises, and never have. Even as a child I always peaked at my Christmas presents. Hell, I remember when Generations came out, I had the novelization (or juniour novelization, to be more accurate) several days before the movie's theatrical release, and the first thing I did was read the last chapter. I don't usually do that with books, but since this was a movie I had to know how it ended. Of course, with this and Trek XI I can't do that since novelizations are released after the movie's release. Okay, that's not an Abrams thing, a lot of movies are doing that these days.
Yes, I admit, I'm a spoiler whore and that's not going to change. And maybe it is detrimentat to know everything in advance, but not relvealing anything is simply another extreme. And could potentially be detrimental, there are those who argue that complete mystery as to the plot worked against Super 8. Unfortunately this is a theory that can't be proved since everyone else reveals something about their movies before release.