Poor design choices by the development team is my guess. I've been trying to use DHC's on my Dreadnaught, but... it's just not effective. Unless I'm in an STF fighting slow as molasses borg cubes, most of my time is spent turning to try and get my 45° arc towards the enemy. Even then, it's just not worth it. You'd need to triple stack high level turn rate consoles and pump all the points you can into turn rate abilities, boff turn-rate enhancers, etc... and by the point, you've cut out so much of your usefulness that it's no longer worth it.