Hear me out. In the star wars universe the main weapons are laser based (primary weapons, turrets, cannons, baster pistols / rifles and even light sabers are laser). But flechettes are needles and/or razor sharp barbs. Every pilot should be terrified when their cockpit is punctured and that precious breathable air escapes into the vacume of space. I don't believe ray shields can stop metal shrapnel since battle droids can walk through ray shields.
For these reasons the flechette cannon and torpedo should double the stress, where as tactians and the like are just very keen crew members that help pilots get the most advantageous spot making their target stress having to outmanuver someone who's whole job is to give their pilot the upper hand.