First, PD was modified recently, so its not nearly so powerful, but even at its best it was defeatable, just expensive to do so. Scout defense made PD overpowered, not the PD itself. I've found that sending 10 fleets of one SB each is enough to easily defeat PD defended inactive planets, usually losing about 2 SB. Against active players 10 fleets of 500 destroyers each has worked for me, generally leaving enough ships surviving to take over the surrounding planets once the PD is down. Now overlapping PD, that is something I haven't really had to worry about yet. Perhaps you would like to share your experience?
It takes 6 million steel to kill 1 PD that costs nothing.
