Using real dinosaurs

But it would have been better if they did this

Let's not forget that one of the earlt concepts of Jurassic world looked like this: https://goo.gl/h54tp6

T Rex roar was a warped baby elephant and the velociraptors were warped dolphin noises
Source: commentary on JP 1

Was it also in the commentary about the t rex getting too wet from the rain and they'd have to stop to dry her off and then start again? I remember seeing that somewhere, but I can't remember where. The water accumulation made the mechanics jerky, if I remember correctly.

Yup! It was the special effects dudes that did that portion of the commentary. I love those guys

Awesome, thanks!