I'm talking like, you know how they heave reptile houses at zoos? Im just saying, a lot of really small critters would be perfectly happy in an exhibit about the size of the hatchery holding pen.
Zoo tycoon did this; with the small pre-built exhibits. And yes, it was bad there because that was all you had. Currently we have the ability to make huge custom exhibits for the big guys; having buildings like this for the little guys (which we arent likely to get as full-sized dino exhibits due to thei size) would be a great compromise.
You could have a small dinosaur house, an ancient amphibian house, ancient insect house, ancient aquarium, small pterosaur house...
It would add an incredible amount of variety to our parks, and it wouldn't even have to be that resource intensive; just canned animations of the various critters skittering about as part of the building.