Well I have to report that I was really curious how the game would have gone if we had time to play beyond Turn 3, where we stopped. I decided to start over and see what more optimum moves might have resulted in.
I did basically the same setup, and played solitaire with very similar moves on both sides. I was able to adjust some maneuvers to better line up the plasmas and got off all my plasmas. I used the same IDF situation, etc.
Turn 3 results were similar, with a D5W and E4 killed, F5 crippled. The Gorns lost a HD, with the other HD losing all it's shields. I did manage to hit with 28AD of plasma this time, instead of the previous 15-18AD.
Turn 4, I moved the 2 cruisers left and right, head on to each other about 10" apart and reloaded. The Klingon frigate swarm followed as expected, and the 2 D5W went after the CM, with the C7 on the CM's 11'oclock about 12" out. The crippled F5 was destroyed.
The Klingons managed to damage the CM to 4 shields and 10 internal hits.
The Cruisers and BDD reloaded their torps. The HD with damaged shields boosted and rolled a "12".

It wandered off to the edge of the battle and was ignored.
Turn 5, the Cruisers and 3 BDD were reloaded.
The HDD boosted shields again and brought them up to nearly full.
The CM backed up, and the 2 D5W and frigates followed it. They unleashed a savage disruptor and drone attack on the CM. Most of their phasers were on IDF defending against plasma again. 4 of 7 ships made their IDF roll, and the 2 D5W overloaded disruptors.
I was able to concentrate plasma fire on only 2 targets this time (D5W and F5, though it was on the F5's front shield). In the ensuing plasma launches, another D5W and F5 were destroyed and the C7 taking a real phaser beating on it's shields which held. A BDD and the CM were crippled. The Klingons decide to run away.
So I guess I am posting this to say that had we had time to continue the game, the Klingons probably would have lost (barring some major error on the part of the Gorns)...that second plasma salvo was rather decisive. I shouldn't have complained quite so bitterly about it like a putz, and I apologize for sounding like a whiner.
Edit*** my opponent had this idea that we're going to playtest next time:
Take the defensive fire against each plasma, one volley at a time. So, add up all the phasers on a single plasma from a single ship. For each two points of phaser damage done, reduce the plasma by one die rolled. Phaser outside the kill zone are going to have a harder time damaging plasmas. Odd points of damage don't affect plasma and don't accumulate between volleys.
Example... Ship A takes a hit from a Plasma S doing 4 dice of damage. Ship A fires 2 phaser 3s at the plasma one of which hits. Since that phaser by definition in the kill zone, the plasma is reduced to 3 dice of damage. Ship B at range of 6 fires two more phaser 3s at the plasma, one of which hits. However, since it is outside of the kill zone, it only does 1 point of damage, which is then dropped. Ship C at a range of 8 fires and hits with three phaser 2s at the plasma. again, it's outside of the kill zone, so 3 points of damage are done to the plasma reducing it by 1 die of damage. However the odd point of damage from Ship B and Ship C are not combined but are instead lost. Ship A takes two dice of plasma damage.
What this will do, is that a ship defending itself with it's own phasers will do so quite well, however, a ship using IDF to defend another ship may have a much harder time having any effect.
Example: A D5W defends itself against 6AD of plasma with 6 Phaser-1 under the current system. A nearby ship on IDF adds 2 phaser-1s to the defense.
5/6ths of the D5W's phaser-1s hit, reducing the AD to 1. 2 phasers fire from a nearby ship, with one hitting and reducing the AD to zero.
Under the new system, the D5W scores 5 of 6 hits, all of which are in kill zone (2 pts each) and reduce the plasma to 1AD. However, the nearby ship is out of kill zone, and scores only one hit, which is not enough to reduce the last AD of plasma...which hits the D5W.
I suspect the main result of such a change will be to encourage any ships using IDF to remain within kill zone range of each other so they can be most effective. I'm not sure it'll make a major difference, but we'll see.