Back in 09 before Dominion, IT and NC used 100+ unsieged dreads all the time on PL dyspro moons -- mostly because they were too scared to siege. Dreads haven't changed much since, but their role has been totally co-opted by supercarriers and titans.
Boosting dreads isn't the answer, at least without new anti-capital AoE mechanics or sov redone. If you do make unsieged dreads viable with current mechanics, then you'll just have the next NC/IT blob with 500 unsieged dreads. I'd rather CCP just remove titans and supercarriers from the game.