I always disliked the crossection book version of the Y-wing panels. The design was lazy and didn't take into account what the lines of the Y-wing cockpit were implying- Yes, you can recognize it instantly as a Y-wing, but the panels don't look like they have any purpose or style.
Of all the original trilogy designs, the Y is the best example of the 'panels removed for effeciencty' idea. The X-wing doesn't have a lot of exposed grebblies, and the Falcon at most has a few panels missing. The Y has always implied that it has the most exposed 'guts', much the same way as the Episode 1 C-3PO. I don't you can extrapolate the shape of the 'skin' simply by looing at the shape of the 'guts'.
This new CW design at least makes sense given what we see of the original 'skin'. Plus, I actually like the idea that it's somewhat unrecognizable at first glance.
The new design is a little clunky- I always envisioned a 'bit' more curves to the body panels. I actually attempted my own version many years ago:
http://flickr.com/photos/10867551@N00/sets/72157601823414575/
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