I didn't change anything with the pirates between versions. All I can say is it's because of the random options. I have no idea what it uses to decide how many ships to send. The max fleet supply is set at 320 and the number the game sends far exceeds that. So... It's basically not playing by it's own rules.
Just to test it, I set the max supply at 100, leave the minimum at 1, set the game to quick start, and do nothing but send scouts out. No building anything other then the scouts, no improving my planet, no expansions, no research, nothing... I figure this should eliminate all of the other random things like planet juiciness, strength per planet, strength per cargo ship, and strength per bounty (which is zero at raid launch time) and here is what is sent after me:
Total supply used = 896
Roughly nine times the max, roughly nine hundred times the minimum which it should be using against me considering I have damn near nothing at raid launch.
Personally I think the whole random side of things is completely broken and will probably be switching it back to required in the future just to keep the numbers manageable. At least there I can set the minimum to be 1 and the max to be something reasonable and still maintain varied numbers of ships. Just my thoughts on it.