Rob,
I could give you all the technical reasons why the further-attached your fletching system is, the more "steerability" and guidance it has the capacity to offer. Think about it this way: The further forward your fletching is, the more likely the arrow is to want to "swap ends"... taken that to an extreme, it would only make sense to move the fletchng as far back as possible.
Or, I could just be be honest and say.. "Never thought about moving them anywhere else than there. "
