One interesting thing i thought about is, what if the reason the new Pacifista are children is because they were made not along time ago and are actually able to fully grow but need a little bit more time. Which would mean they are getting stronger once they are fully grown. With the Germa we know you can mass produce humans and it takes about 5 years to grow a 20 year old human. Those new pacifista might grow even faster who knows.
Or Oda just wants to see children getting beat up as he seems to like