Actually, I've found drones fairly useful so far; launching just a couple drones against small colonies will wipe out the colony. Large colonies still need a fleet action, but against races that rely heavily on seekers for their weapon platforms, drones could be used to soften up the planet before the fleet moves in. Of course, fighters would probably be just as effective for this, as seekers can't target either drones or fighters...
I've also successfully used drones against single ships; I have a number of drone-launching bases (paired with space yard bases, of course) scattered around my territory & my neighbor's territory, so it provides a low-maintenance (and low-profile) attack platform. I say low-profile because the AI concentrates on following my big fleets, and ignores the bases.
