Yeah, releasing extinct animals back the wild should only apply to animals that have gone extinct recently otherwise it would just cause ecological damage and likely lead to other animals going extinct.It would be interesting to have extinct Animals not only just to have them in the Park, but also to help Scientists learn more about them and to release Animals that where wiped out by Humans back to the Wild. If there will be this kind of Expansion, I think there would be no possibility to release Dinosaurs back to the Wild because the Introduction of new Species to a Ecosystem can cause big harm to the Ecosystem
Dinosaurs and other long-lost animals would be about research and education only. Living history, basically.
They could be the sort of exhibit that helps increase the attendance of scientifically-minded guests and children.