Utahraptor would be dope. I also really want Therizinosaurus, Deinocheirus, Psittacosaurus, Amargasaurus, Quetzalcoatlus, Liopleurodon and some sort of Plesiosaur. More visually distinct carnosaurs like Acrocanthosaurus (probably not happening since we're getting Giga), Masiakasaurus, Cryolophosaurus, Sinosaurus, some less bulky ones like Elaphrosaurus/Coelophysis, or more basal saurischians, would be nice too.
Also something they can give feathers without nostalgia fanboys crying about their childhoods being ruined, like Archaeopteryx, Oviraptor, Gigantoraptor or Microraptor. Though Therizinosaurus and Deinocheirus also need feathers, natch.
We're five movies in and there's so much untapped potential. Fallen Kingdom at least give us a lot more different new animals. So if anything I can appreciate it for that reason.
Afaik, recent discoveries suggest T-Rex was bigger. At least, it could get bigger, based on the fossil evidence we now have. T-Rex also had a stronger bite. Maybe we'll find a Giga bigger than a T-Rex in the future. But right now, it goes Spino > T-Rex > Carcharodontosaurus > Giga.
