Children's programming does not need to be dumbed down, even for very young audiences. Dinosaur Train is a perfect example of that type of intelligent and fun programming.
My toddler loves Dinosaur Train, and I don't mind him watching it because it promotes exploration, diversity, tolerance, different family structures, vocabulary, questioning, science, and a boatload of dinosaur facts. As an adult, I've learned some new things about dinosaurs as well, and the paleontologist point of view and fact/fiction verification at the end of episodes is a strong feature that enhances the show. There is a nice balance of imagination and verifiable fact that makes this show fun and educational.