Im not to fond of that "documentary" either,it did have a lot of good elements,like using lesser known dinos and embracing the dinosaurs are related to birds ide and telling adventure like stories instead of just showing just the facts ,but it was it half assed attempts at comedy,horrible mood whiplashes and over anthropomorzation of the dinosaurs is what brings it down.
The animation is rendered pretty well,i like how all the creatures have detailed textures with wild color schemes and the models are pretty accurate, but it not integrated well with the background and there are a lot of scenes where it is obvious that the animation is slapped on to a rather blurry still photo and as you said it doesn't move very naturally at all.
Also another problem I have with this show is that its needlessly gruesome at some parts, especially when they have the Torvosaurus bite off the Allosaurusus crotch and possibly his testicles,yeah who in the right mind thought that was a good ide to show.
That episode could have been titled "predators dying hard". I mean, decapitated and runs around while headless? Gets the lower jaw ripped off the skull? Bitten in the crotch? Goes after a juvenile even though the parent is struggling to get up, giving time for said parent to counter attack-and doesn't bother dodging?
Or the one that came up with the scene where the baby pterosaurs go on their first flight out of the nest only to bang into a cliff and die and get snatched and cannibalized by a adult male pterosaur that is played like a cartoon clip with funny music rather than a tragic sight,or showing their mother be stupid enough to force her last hatchling to jump out even though there's a pack of hungry crocodiles below.Indeed the people were sick.
Or the proto-mammal being kicked into a predator's mouth. Or where the biggest frog ever gets squished. Or the sexually frustrated Gigantoraptor. Or the rather sadistic behavior of rival males in trying to bite of both front limbs or biting off the sexual attractant. And why are the mothers so careless?