Really? Most of my games towards the 3rd week i get at least 200+ pirates going for planets, sure it splits up most of the time, i got unlucky once and had 217 on the hub world which was impossible for me to defend. Not sure if thats normal but i figured it was normal since it happened often that i had to fight off that many, just mostly split usually.
Edit: Im in a week 3 game just to be sure and yup again i got pretty much 300+ pirates, 155 + 88 + 35 +65