Also, assuming there's more dinosaurs coming in DLC (they've already confirmed Fallen Kingdom stuff) the space problem will only get worse and worse as time goes on. The early islands I can understand being smaller, as they're basically tutorials, but Sorna and Nublar need to be a LOT bigger (I haven't seen Sorna myself yet, but what I've seen online shows it has the same problems as Nublar). I would expect to be able to have every species comfortably fitting on Nublar, with enough room left over for all the buildings for the park area. Also, yeah, the area looks like a generic valley in a tropical area, not like Nublar. It doesn't even have the river or volcano.
I'm definitely hoping the devs increase the size by at least four or five times, but I can't see them doing so.