Brown Bear, Brown Bear from Carle himself is mediocre junk. It's just colors and animals, and has no character, no narrative, no arc.
The Hungry, Hungry Caterpillar is an amazing, astounding masterpiece. It is usually printed with a sort of dynamic tactical approach with different page sizes, holes in the pages, the story has a real arc, it teaches biology, it carefully works in numbers and days of the week and the idea of time frame… it's a true stand-out.
Most of Carle's stuff is somewhere in the middle, though he has a few other superb ones.
Just like art for older audiences, there really is a range. You could say that all movies are the same: people having conflicts and doing stuff. On some level, they're all dramatic and simplistic.
It's not mere taste. What makes a great book or movie for any age is not total relativism.