To be truth the Nublar map in this game for the JP era is kind of small so you wouldn't want to take up space with useless nonfunctioning decorative items like the raptor pen from the RTJP DLC. At least that's how I see it. It didn't do anything in the first game. It was just a nice Easter egg.
I completely agree with the aviary. I should be able to go into the sandbox and choose to build a JP or JW park and have a JP themed aviary to choose from. The campaign aviary would be fine or one with some kind of JP theme. But there was never a aviary in the movies that anyone could see much of. But they still managed to make a nice looking one for the RTJP DLC.
Also I have found out that you can get the aviary in the game using sandbox with a JP themed park build. You need to be on PC or a new console and choose both buildings. The glass domed aviary is in the enclosures tab. If you don't mind using the JW style glass domed aviary in your JP build. They could probably squash most of the complaints by letting us have access to the campaign game assets in sandbox when we complete the campaign, plus the maps and resize some of them for sandbox. People would just put down the DFW aviary and enjoy it. It would work till they come up with a JP themed aviary.
I think they took the whole a more authentic Jurassic World and Jurassic Park experience a little too literally. We know there was no aviary in the movie. But we would still like one.