My last playthrough I always kept 3 Enforcers in my fleet to the very end for several reasons:
1) I could get all I wanted from pirate fleets, and they were basically the best destroyer I could get from pirate fleets.
2) With skills for reducing D-mod effect, and reduced maintenance due to D-mods, they were super cheap to keep around and use a lot. Even with degraded engines they keep up with capitals and cruisers.
3) They have medium guns pointed in lots of directions plus 150 omni shields, which with front conversion, goes to 300 degrees. This gives them a huge area of control versus frigates.
4) 420 seconds peak performance. This is the most crucial!
So I'd use them (under AI control) in every battle just to occupy stuff until I could deal with it. They cost nothing to acquire, cost very little to operate with 3+ D-mods (even increased maintenance is a net positive if you field them often enough), you get so many that you can pick and choose which D-mods you want, and actually last for a full battle. Toward the late game the problem I have with frigates and most destroyers is that they run out of operating time in a big battle, while cruisers and capitals take too long to recover to handle multiple fleets, especially with pursuits. Enforcers don't have either of those problems and it doesn't matter if they die, anyway. So I can use them repeatedly in battle after battle and choose which other ships to accompany them based on the enemy composition.
The loadout was generally Hardened Subsystems, Efficiency Overhaul, and:
Flak: HMG, 2x Dual Flak, 2x Flak, 4x Swarmer, IPDAI and gyros.
Long Range: Heavy Mauler, 2x HVD, 2x Vulcan, 2x Annihilator, ITU
Discount: Mix of Heavy Mortar, Arbalest, Heavy Autocannon in front. More of those or Flak/Vulcan (whatever's laying around) on sides. Single Sabots/Hammers. And Unstable Injector.
Missiles are not really important on these (particularly the budget) because they are supposed to stick around for the whole battle way after the missiles are gone and there's no budget for them, so they're the first thing to drop.
I don't like flying these things around because they're so slow, although the long range one is OK. But if I plan to fly one I always give it front shields.
