Err, well, back to topic anyways.
I'll just repeat my statement on this thread.
The Hecate has a reputation for being an odd-looking, impractical destroyer with poor anticapital firepower, and shouldn't be a worthy successor of the Orion. However, let's just consider why the GTVA possibly came up with such a design...
The Hecate, yes, it looks odd. Don't you think Volition did it to make it sort of look like "more advanced" than the Orion? With more superstructures, more functions, and stuff? Also, we never really saw the Hecate perform against powerful enemy ships like destroyers. We saw the Aquitaine take down a Shivan corvette, the Tiamat, and that's the most the frikkin' destroyer could really do. Having let's say, twice as much BGreens as an Orion would be useless if all a Hecate would destroy would be a corvette, and challenge a Juggernaut that would destroy it in a few seconds, if it wouldn't jump out before its 4 rays of death chewed it apart. Besides, wouldn't the fun be eliminated if the Aquitaine decimates the Tiamat in just a single volley of beamfire?
However, as I've alreay mentioned before, the Hecate's antifighter defenses are quite poor for a skilled pilot, but still better than an Orion's. Hell, it has 26 turrets which would fire through the ship. And lots of superstructures which an unlucky pilot would collide to if he were clumsy, stunning his fighter, and exposing himself to an enemy fighter, where he'd then be vaporised. The AI sucks at this point. See Shivans clumsily colliding into one of the Aqui's wierd structures, and watch it gleefully bounce back, as if saying, "hey, c'mon, now's the time to shoot me to pieces!".
Furthermore, I'd say that the Hecate's multiple hangars might allow it for fighters to flank the enemy ("Attack from all sides" sort of tactic). Unlike the Orion, whose one massive fighterbay might mean a little more time for its fighters to evacuate and patrol their mother ship. Hell, we don't even know what could be inside those hangars, apart from mere fighters and bombers. Of course, canonically there's nothing else, but try to think; could there be transports, gunboats, sentry guns, and other sorts of crazy stuff?? With only one hangar, the Orion might have a hard time cramming that all up.
As it is, you could judge the Hecate badly all you want. However, if we think beyond the boundaries of canon, there are tons of possibilities why the GTVA thought of such a design.