I have to say I prefer the turrets the way they are. Well, Grikath and Gothri turrets are really annoying, especially to Arrows and dumbfires, but I can't say that's exactly a bad design decision, and Crossbow turrets really ought to be bad. All the non-Sabre (non-Morningstar, I guess, too) strike fighters being kind of terrible is where a lot of Standoff's hardest strike missions get some of their difficulty from (you'd love those extra guaranteed torpedo hits, pity you need to take a bomber where survival is a challenge to get them, eh?), so giving the Crossbow something that might actually pick Sartha dumbfires off would make some missions way too easy.
Well, by my standards of too easy anyway. I'm aware some people aren't disappointed by missions where they don't fail first time out.