I think making Dreads effective against turrets (they aren't) would go a long way to making Dreads more useful.
And another strategy I haven't seen mentioned - Raid Starships.
They are super effective against turrets with their high damage, quick reloads, high health and high speed (to get in and out in a pinch). Early game they are the best answer if you have the patience to use them and you don't want the early game losses (although if you had the patience to use dreads then you'll LOVE raiders).
Also Infiltrators if you have them. They would probably clean house in a minute or two, no joke, they are stupid good against turrets (annoyingly/overpowered so actually in the hands of the AI, though if you can get your hands on them, nuts to the AI!).