BAH! I still don't buy it. Ya, Warp Drive is suppose too shorten the distance between points, but Distance is not the problem here, its time. So what you are saying is that in this distance of 500 Parsecs, is that the Warp engines actually shorten the distance so that its easier too transverse. So if we use TOS scale velocities, a Contitution Class ship's Maximum Warp Capability of Warp 11.8 (Warp 9.2 in TNG scale) which results in a Velocity of 1649 c (c = Speed of Light). Now granted, The Ship isn't really going faster then the Speed of light, its just warping space too make distance short (or maybe its stretching the ships length much longer, depends on your preception), but this is still a problem with the 500 Parsecs idea.
So if Constitution Class ship's Max Velocity is 1649 c (Warp 11.8 TOS scale), and if one of these Hex's is roughly 2500 Light years across (assuming the 500 Parsec distance, it would still take the the Constitution over two years too transverse that distance. Now, you say that the Warp Engines actually shorten that distance soo it really isn't over 2500 Light years. Ok, if that is the Case then you would take 1649 c / 2500+ LY = 0.6596 Light Year Distance. So at Warp Speed, the Distance for the ship is suppose too be 0.6596 Light Years in Distance instead of 2500+ Light years in distance. Now that the Constitution has shorten the Length of the Distance of the 2 points, it would need too engage its Impulse Engines in order to cover that Minimized Distance. Even if the Constitution Engaged its Impulse Engines at 50% of the Speed of Light (and we already know that the closer you get to the speed of light, the more Time gets distorted (slows down) which in turn means the Impulse Engines would consume less fuel and force less thrust foo move) it would still take the Constitution over 2 years of time too transverse that kind of distance under this theory. And this is if the Constitution was at Maximum Possible Warp, I thought I heard that a Consitutions Cruise Warp Speed is something like Warp 7 maybe Warp 8 which are only a Fraction of the ships Max Speed. And this situation becomes even worse when dealing with Early Warp designs or god forbid the old debate about the Romulans and their "sub-light" ships (which still doesn't make any sense).
I'm sorry, but this is just another inconsistancy that Steve Cole didn't want too mess with and wanted too keep as close too the Starfleet Technical Manual as possible. Maybe he did this for legal reasons, I don't know. But I can't imagine anybody would sue him if he just Made the F&E Hexes a distance somewhere between 20 to 40 Light Years. Anymore and it just doesn't make any sense.