Dan,
Since your players are SFB guys, ask them this: if you have run some large squadron or fleet battles, what kind of drone hit rates were you seeing? Personally, and this has been many years, I recall the rate was 3-5% of drones fired from medium-long range hit. It was too easy for every ship in range to dump their phasers/drones/ADD onto the incoming waves. In ACTA:SF it isn't quite so easy to defend your neighboring ships against drones.
Drones are supposed to be nuisance weapons for the Feds/Klingons; again, how many of them actually hit? Even with Kzinti dumping 12 drones onto a Klingon D5 for example, you probably won't see many hits until a) you run out his ADD2, and b) he'll use phasers/tractors on any survivors. You have to run his ADD out, and even then you'll lose the majority of your drones to phasers. But it diverts phasers (and sometimes his drones) from being fired at you.
Some ways to increase your drone hit rate:
Concentrate on him from the get-go, and run his ADD out (this is dependent on luck really).
Try to hit him from an angle that fewer phasers bear on (against that D5, attack from the Fore Arc, as his phaser-3s don't bear).
Maybe hit him later in the turn after he's perhaps fired some weapons at your ships?
Fire your direct fire weapons first, giving you a slight chance of a Weapons critical hit that will reduce his odds of hitting with defensive fire (not to be counted upon, but it does happen).
As for slowing down the game, I find the worst offenders are defender agonizing over what weapons to fire in defensive fire, and plotting out your moves. Putting a dot next to a weapon system for each die fired is a non-issue to me. Plotting out moves is the worst time-spender, IMHO. I am guilty of this, trying out several possible moves and taking too long. I keep telling myself, fly by the seat of your pants and make your move faster. If you fret over the optimum move, it takes more time to move.
As for my thoughts on IDF, I see Billclo's point, but when a ship gets shot with another ship full of plasma and has only itself for defense you may as well kiss it goodbye (in our experience). Without support from other ships it's almost an I win button against everyone except Klingons (who have phasers to spare in arcs that are better than the originals).
Well in SFB, that Gorn BC dumping 100 points of plasma and 4-6 phasers in your face against a cruiser is pretty much a "I win" move if you don't have a Wild Weasel. Figure 60-70 internals plus more from phasers = instant crippled cruiser. Not always the case in ACTA:SF. Try that in SFB ; okay, you used up your 6 phaser-1s at short range, that's 4 pts per phaser damage, x 6 = 24 pts damage, halved against plasma = 12 points of plasma lost out of 100. Big whoop.
It's weird, you can basically take no damage because you've shot down all the plasma dice, and then when you reach the defensive fire threshold, all of a sudden defending ships start blowing up.
