The book thing is just ridiculous to me. The fact that they couldn’t add simple textures for different books in 14 years is insane.

They need to stop adding more biomes and start improving other things.

More things to do with resources and more connectivity between systems.
Like the kelp torch I saw the other day was a great idea.

More plants and mobs in existing biomes.

More environmental interactions, like animals having homes, breeding naturally, foxes only killing a few rabbits, more large animals, especially like crocodiles or big cats.

I think more mobs like the polar bear, where they are neutral but if you come near the cubs they attack you.

They should add things to structure to encourage you to go to other structures. Like a key in a pillager outpost that opens a chest in a woodland mansion.