The following contains a major spoiler for Jurassic World: Fallen Kingdom.
Steven Spielberg is the man responsible for turning Jurassic Park from a popular novel into a massive movie franchise. However, the newest movie makes some pretty massive changes to the world he started. While it's conceivable that Spielberg might not be a fan of the major twists inside Jurassic World: Fallen Kingdom, the truth is that he was actually all for the twist involving the little girl Maisie. According to producer Colin Trevorrow...
[Spielberg] really dug the Maisie element of it. He dug the way that we were evolving it, and he was really excited about the questions that it leaves at the end as far as where the future could go.
Early in Jurassic World: Fallen Kingdom we meet a little girl named Maisie, who we're told is the granddaughter of James Cromwell's Lockwood, the former partner of Jurassic Park creator John Hammond. Eventually, however, we learn that this isn't true. Maisie is actually a human cloned from Lockwood's daughter, who had died in an accident. The decision to use the cloning technology on people caused a rift between Lockwood and Hammond and the truth was kept from the girl.
It's certainly true that the knowledge that Maisie is a clone raises many questions about what could be coming in the future. The fact that Maisie is a clone isn't even strictly relevant in Jurassic World: Fallen Kingdom itself, which means it's quite possible the character was created primarily for what is to come next anyway.
For his part, Colin Trevorrow, who will be returning to the director's chair for the next installment, also sees Maisie as important, not necessarily as a clone, but simply as a child, as he tells Empire the fact that she has been taken in by Owen and Claire means that their relationship has been changed forever.
I see it as an evolution of the themes that Crichton laid out. It's so much closer in our world than making dinosaurs is. To me, it's a family creation myth. Owen and Claire start off the first movie as these sexually-charged Hepburn and Tracy characters, and in the second film they're taking on much more responsibility as adults, and by the end they're parents -- they have this child, and they're driving off into an uncertain future. And that moment when Malcolm is saying irrevocable change, that is happening to them and it's happening right now. I just found that very effective to put that in the context of these people who are evolving in a big way over the course of this story
It certainly can't be said that Jurassic World: Fallen Kingdom didn't take chances. In addition to creating this unusual new character, it also finally brought the story off the island and changed the world in such a way that Jurassic World 3 is destined to be the most unique film in the franchise since the first one was directed by Steven Spielberg.