I agree that they're not really that tasteful, and tend to take up room that would be better served for (living) animal exhibits. But the recent ones that they've done tend to really highlight the dangers of habitat destruction and human encroachment on an ecosystem and the numerous species living within it -- dinosaurs are extinct, after all, and teaching kids what extinction is and how it happens is important, I think.
My zoo will be opening up an exhibit called Dinoroarus this spring, as a temporary replacement for the now-inaccessible Children's Zoo (they decided to permanently close it due to Covid-19 and are working to reimagine it as a new zoo space in the near future). They plan to house several bird species within it so that they can stress the evolutionary linkage between the dinosaurs and their modern relatives.
As far as placing living species in such an exhibit that would have actually been around back then, I'm going to say crocodiles, turtles, and small lizards would be appropriate.