The skeleton of the extinct Moa. Not hard to believe dinosaurs and birds are closely related. Evolution has been a wondrous thing. Think about how closely related all mammals are, just 2-5% DNA separates a human from a chimpanzee. Between humans, diversity in DNA is just 0.1-0.4% Not all dinosaurs were necessarily avian though. So you could still have had normal scaly skinned reptilian style dinosaurs as well. I remember reading how some scientists argued triceratops, stegosaurus, along with sauropods probably had scaly skin etc.
All that said, just for the sake of continuity and what I grew up with, I wouldn't have wanted new and radically different dinosaur designs. I know how backwards that sounds, but that's the point of watching Jurassic Park. I would've been fine had they showed feathered dinosaurs and new more accurate designs in the peripheral distance, but nothing major like revamp of T-Rex or Raptor's to accommodate the latest research.
That all said, I also didn't want the new rumored genetic monstrosity they created for this film.