I, personally, disagree. It gives dinosaurs a good 1-tribute beater, not to mention one of the only easy-searchers in the whole game. Also a THIRD WAY to special summon dinosaurs, so that's pretty nice. Mai's rewards... were probably worse. Vennu wasn't good, Princess of the Ice Barrier and Swift Birdman Joe are one-turn solutions. I don't see Amazoness often.
Princess of Ice Barriers is a no brainer in a Ice Barrier deck. Swift Joe is also a good 1-tribute beater with a good effect and Amazoness will probably have support later.
Giving Jurassic World when you have a skill for that is useless...
I disagree. Take, for instance, Destroyersaurus' effect. It sends itself to the graveyard, allowing a search. If you already have the card on the field, then Destroysaurus gives you the discard cost to summon it back by way of Fossil Excavation. Speaking of Fossil Exc, by sending Destroyer to GY, it lets you use Fossil Exc, meaning it lets you bring out Driceratops or B. Tyranno early on.
With J-World pretty much the only big card they can't beat over that's seen relatively commonly is Blue-Eyes. With Jurassic World they can beat Naturias easy. If they're able to act fast enough using cards like Survival Instinct they can stop Nephthys and Red-Eyes decks. They're not super OP, but bad? Definitely not.
Naturia can be really annoying if you're playing a good build. The advantage of these dinosaurs, though, is how incredibly inexpensive they are. They might not be as good on average as Nephthys, but not only can they win, but most of the cards they run do not require gems. I stand by the statement that dinosaurs are one of the strongest F2P decks out there right now, but are very underestimated.