Again, we were talking direct fire weapons (phasers) in which firing arcs are important.
Begging the question: ARE THEY? Phasers are directed energy weapons, not technically "direct fire" in the sense being used; theoretically, all you need for 360 degree coverage is one phaser on the front of the ship and one phaser on the back of it; the presence of the extra emitters doesn't seem to have alot to do with the need to cover all firing arks and more to do with the need to concentrate more phasers on any particular target (though we've only ever seen this firing mode in STXI, where even the side-facing phasers are fired at forward targets).
That's why I'm saying the difference between turreted and fixed weapons is just a matter of what kind of target you're going to be shooting at and at what range. Even a turret-based missile launcher makes sense if your missiles are being aimed at targets only a few hundred meters away, but beyond that range it doesn't make alot of difference.
Aircraft are poor parables for starships in that they are relatively fast and manueverable. The better parable to starships (in the Star Trek setting) is the modern day sea naval ship.
Respectfully disagree, remembering as I do the incredibly rapid banking turns made by the Enterprise-D in "Encounter at Farpoint" and similar combat maneuvers throughout DS9.
Actually, the most appropriate parable to a starship would be a large tactical bomber equipped with radar-guided machineguns and air-to-air missiles; this could develop in a world where some type of exotic unobtanium alloy has been developed that allows for the construction of absurdly huge, heavily-armored aircraft that are incredibly difficult to shoot down. The heavier bombers would have the advantage because their large size allows them to carry bigger weapons and in greater number that can repel or destroy smaller and less sturdy fighter planes before they can deliver a killing blow. Adding guided missiles to the package means you could have something the size of a B-52 packed with up to 40 Sidewinder missiles and some kind of FLIR targeting pod that can fire those missiles at any target in any direction.
Now, sure, you can make the argument that the smaller more manueverable fighters would make mincemeat out of the bombers... but this is only in a world where the race between weapons and armor heavily favors the weapons. In Star Trek, it doesn't; shields can soak up an awful lot of punishment before they go down, so what you're really looking at is a B-25 Mitchell covered from nose to tail in a ten-inch sheet of unobtanium armor; BF-109 making an attack run has to put ALOT of firepower into that bomber to shoot it down, while the bomber's more numerous and incredibly accurate guns can chop those BF-109s to pieces before they can finish the job.