It's funny. The first movie doesn't really lend itself to any sort of traditional sequel. To tie to the previous movies, both The Lost World: Jurassic Park and Jurassic Park 3 involve convoluted plans to trick or convince people from the first movie to return to face dinosaurs again. There are running jokes in both movies that have Ian Malcolm and Alan Grant, respectively, acknowledging that they steadfastly refuse to return and then end up right where they said they wouldn't be. While some show new dinosaurs and continue the lore of the franchise (a little bit), they both almost instantly revert to traditional monster movies for the 2nd and 3rd acts. It's the action of the first movie without much of the soul.
What's funny is that Jurassic World actually makes a lot more sense as a traditional sequel to Jurassic Park. While John Hammond failed to bring his park to life, Simon Masrani realized that it could be done with a little more precaution. The greed and ambition from the first movie lives on, and the park succeeds until more greed and more ambition wins out again. The film is, in a lot of ways, a rebootquel as it treads a lot of the same water as the first movie with bigger setpieces and a lot more collateral damage since the park is still in use. It also works because the only returning character (Henry Wu) belongs in the movie as a former employee who would still be actively involved in dinosaur production.
It definitely doesn't have the same soul as the first movie, but you can definitely see the resemblance to the original. And you can tell that the people that made the movie were huge fans, and they wanted to honor the franchise. As a huge fan, I thought they succeeded. I've rarely had as much fun in a theater as I had watching Jurassic World.
Fallen Kingdom has the same flaws as the first group of sequels in that they have to trick characters into coming back to places they'd never realistically want to go back to. And without ways to get innocent people onto the island, it has to resort to the trope of bringing the dinosaurs to the innocents.
What's funny is that I think I would've tried to stick with Jurassic World's roadmap - keep the park open. Yes, Masrani would be riddled with dozens (if not hundreds) of lawsuits regarding injuries and deaths in the park (although they might've forced guests to sign something that alleviated the risk for some of the minorly-injured guests). It would've made the park a lot harder to run because of massive risks involved.
But Jurassic Park ends with most of the dinosaurs released from their cages and major damage to most park buildings. If I remember the ending of Jurassic World correctly, there would've been major damage to Main Street but the damage to the park itself was minimal. The only dinosaurs released in the incident were the pteradons (which were taken care of before the climax of the movie), along with the Indominus itself (killed), the T-Rex, and one surviving raptor. The rest of the dinosaurs would've been contained already (outside of the ones killed by the Indominus on its way to the visitors center).
At the end of the movie, there's a ton of human damage but not that much damage to the park itself. It, hypothetically, wouldn't be that difficult to get the T-Rex back under control. Blue might be harder to catch, but they'd probably just use the same tactic from Fallen Kingdom to get her back.
Within a few months of renovations, the park could easily be cleaned back up. Yes, the reputation of the park was damaged. Yes, Masrani would be in some financial trouble. But the park was *packed* during the events of Jurassic World. There were a couple dozen major brands in use on the island (including at least one hotel, stores, restaurants, etc). I assume someone, if not Masrani Global itself, would see profit still to gain. After all, people flocked to Jurassic World even though the public was aware of the incidents at the original park and in San Diego.
So that's where I would've set a sequel. Owned by a company that wants to salvage profit (maybe BioSyn finally gets control) and doesn't care about anything else. Where park attendance is understandably fluttering. Where they start to take more chances and ease up security to get people interested. Maybe they open up the park to limited hunting for special guests? If they want dinosaurs on the mainland, maybe they start to bring some dinosaurs on "road shows" to try and get people to come to the main park?
Just imagine a tarnished Jurassic World with limited security, collapsing infrastructure, and expert-level greed and ambition. It'd essentially be the nightmare that Malcolm is actually talking about during Fallen Kingdom.