These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Jumped the Shark: For some fans. The first book was a fascinating voyage of self-discovery. A few fans had some problems with The World Beneath, citing a rather irritating anti-technology plot along with turning elements that were left very mysterious in the first book into a more generic lost empire with Power Crystals, but they still give the book overall high marks. However, in First Flight, the plot had degenerated into an unremarkable action-adventure (it came with a board game) featuring You Meddling Kids. Fortunately, Chandara was a return to form.
Mary Suetopia: To an extent, but Guerney has stated that this is intentional.
They Just Didn't Care: The TV miniseries. It dumped the Victorian-era setting and naturalist protagonists for modern-day teenaged boys right out of the CW casting offices. (This completely disregarded the fact that every single Dinotopia book, including the spin off novels written by other authors, had been set in previous centuries - turning an easily justified trope into a more ridiculous variation with some kind of magical continent that never showed up on satellite imaging but could still literally be reached by riding the back of a dolphin.) It plays the Anthropomorphic Shift and changes the Code of Dinotopia (which was originally a acronym for SOW GOOD SEED) to something else that doesn't make sense. And then it Flanderized the Dinotopians' peace loving ways into naivety and ignorance of the outside world (in the books Dinotopians were quite enlightened) and turned the intelligent Barbarian Tribes of carnivores in the Rainy Basin into standard Prehistoric Monsters (as well as completely ignoring the fact that carnivores never leave the basin to wreck havoc). Finally, it turned Dinotopia itself from a peaceful utopia mostly devoid of technology to a static anti-innovation regime dependent on Sunstones to keep out the carnivores.
And the television series that followed took it Up to Eleven
It's best to not even mention the animated film.
The worst part is that the mini-series has experienced some limited Adaptation Displacement among younger audiences. They view this trash as THE Dinotopia.
What Do You Mean, It's Not for Kids??: The first Dinotopia illustrated novel is a book with loads and loads of illustrations. And it involves talking dinosaurs. It never had a chance. Gurney has stated that his books are for all ages; he likes media where things can be enjoyed both at a shallow surface level and also when more thought is applied.
The spinoff novels on the other hand, are definitely meant for kids, though a few of them have crossover appeal. Have we mentioned the Knights of the Unrivaled?