3. John Hammond (Richard Attenborough)
His character, a genius scientist philanthropist, was what made Jurassic Park possible in the first place. Without him, we wouldn't be talking about Jurassic World. A loving grandfather with a brilliant mind, you couldn't help but feel for him in Jurassic Park, as the dinosaurs broke loose and he realised that his actions had put Lex and Tim in terrible danger and that his life's work had been compromised. Whilst a small part, his role in the sequel proved itself to be an essential one. Yet again, he was the man who brought our heroes back to the island (or, at least, by convincing Sarah to go, he inadvertently brought Malcolm back, despite his protests). And Hammond was the man to address the world after the events at the end of the film, realising that his dream of a tourist park was over and that the dinosaurs needed to be left alone. His absence from the third film was noticeable, but I think there is still room to explore this man and his legacy.
How He Might Return... In true Spielberg-style trickery, I can imagine a 3D holographic moving image of Hammond guiding guests around the theme park, with all that trademark delight he conveyed in the first film. A great chance to witness an younger version of his character before the dinosaurs literally tore his park to shreds. Or as possibly a tragic figure, too. Considering the events of The Lost World: Jurassic Park and his absence from the third film, we can assume that he lost control of his company, InGen, forever. To be cut out of his great achievement and yet have his image used to promote the park? And as things fall apart, it might well feel like we're coming full circle with the untimely events of the first movie all over again...