What is expected to happen in Minecraft 1.17?

We already know roughly that the current snapshots for 1.16 will be the last. I asked what could be in 1.17. Dar was kind of a fan fiction that thinks 1.17 will be a major cave update. Others think that there may already be a new combat system. My question: What do you think it will be? Are there any comments from Mojang that I have overlooked? Are there any other hints? I'm looking forward to a little discussion

PS: From me you can also write what you would like.

I think it's a mountain update that brings mountain goats and co. Would also be logical since it would be a small update at the end of the year. Otherwise I could also imagine a cave update.

Mountains and cave. New generation of biomes.

Then the desert and savannah are worked on.

Then swamp and mesa.

Combat system is improved, but you don't know exactly when. The first tests were already available with a snapshot for 1.14.3.