To me, as an aspiring, unpublished author who probably has no idea what he's talking about anyway, outlines are kind of a grey area. I mean, I don't think they're necessarily good. For term papers and such, fine, one needs those to stick with the format of the paper so they don't get flunked out of the class.
But that's just it...outlines force you to stick to a format. It's the very reason I'm incapable of writing screenplays. The scripting class I had in college implanted the formula, and now when I try to write a screenplay, all I do is plug in the values. The characters come out stiff and...well, formulated.
Like I said, I don't claim to actually know anything, this is just what I feel. To me, outlines feel to constricting and it seems like, if everyone is using the same plans to build something, then after a while it will become uninteresting and everyone's stuff will be the same. Just like if everyone's house was built from the same floorplan, just decorated and finished differently.
So, though I might not ever make it to print because of this, I actually try to avoid outlines. I jot notes here and there to remind myself of a scene or character or whatever, but I try to make the characters and world real enough so that I don't have to tell them what to do and where to go. I'd rather them forge ahead on their own.
But i don't know, maybe I'm just flapping my jaws.