The upshot to the DD is that it can dance. Once a CA or BB has taken serious damage, it is almost certainly going to die in its next fight, because it can't evade incoming fire effectively. A DD, on the other hand... well, I've had matches where I was dropped to about 1% hp early on and still managed to get multiple kills and survive the battle after taking all that pain just because I could stay out of sight and volley torpedoes. The Minekaze's really the most effective DD in the game at that, as it gets torps with a 10km range but can't be seen until 6km. Strangely, from what I can tell, the tier 6 and above DDs seem like they're actually less effective torpedo boats (much longer reload times), but they do have better guns, so... *shrugs*
Just a different strokes thing, I think. I HATE playing a BB, for instance, and the grind to CV was a pain in the ass for me.