I definitely agree that they could've just stuck with normal dinos. It easily could've been the place they dumped the dinos that didn't quite meet expectations for what they wanted for the park in terms of attitude, colors, etc., without having to be full-on mutants. I understand the desire to keep going bigger and badder and cooler, but people are enthralled with just regular dinos too (despite what the movies would have us believe- I don't see people ever getting bored with dinos!). While I do think Rebirth course corrected a little bit with getting us back to basics, I'd love to see another simple, no-frills dino movie again soon.
However, I did like the Spinos' redesign. I'm a JP3 defender, especially as far as the Spino is concerned, and I'll always go to bat over that one, but seeing as how that's basically a hybrid accident in its own right, I'm cool with that being a one-off and having more accurate ones elsewhere. Then again, I'm biased; for whatever reason, I've always loved aquatic/marine creatures and stuff, so a more fishy design for the Spinos really hit that sweet spot for me. I'm sure because we got the JP3 Spino just now, it'll be a bit before a Rebirth one comes along in the Hammond Collection, but I'd gladly take it.
Same with the Quetzal. I really loved its color scheme more in Rebirth, and I liked the smaller, but still quite large, size. The Quetzal in Dominion felt too big to me, whether it was more accurate or not. I like that the Rebirth one was a bit more manageable for the humans to interact with (as much as they could, anyway).
But to each their own! Everyone's got a favorite dino and ways they prefer their other dinos. I haven't really disliked any dino or how they were portrayed. I'm a simple guy- I see dinos, I get excited.