If you want a whacky suggestion, make a ship with higher movement than the rest of your ships, put on a single weapon (warhead) and put a ton of shields or armor on board.
Now give it a new strategy so that it will ram things and set the priority for "fighters, fastest, smallest, has weapons". If it doesn't destroy a few clumps of fighters, it should have atleast softened them up a bunch.
Rinse and repeat