What is the mindset behind world gen improvements?

[undone owl]

I am curious how the team thinks about world gen (data-driving biomes, dimensions, jigsaw improvements, etc.) in a broader sense.
Are improvements trying to be shipped into betas as quickly as possible or taken slow, and why or why not?
Is the team worried about breaking worlds in preview versions?
(Long term) is world gen working toward full customization? Which parts are being favored in development first?
What have been hurdles in any world gen processes (deciding best practices, long term vs short term, technical hardships)?
How does thinking about bedrock world gen relate and differ from how it’s done on Java?

Sorry for a lot of sub-questions, I’m curious!❤️

[earnest token]

Lots of sub-questions! I'll try a few.

As a team, we always try to work in an iterative way. We want to ship small things regularly so we can get feedback from you all.

Breaking worlds in Preview - we try to avoid doing this as much as possible. But we don't hold ourselves to the same rigor as we do on retail builds. So Preview builds will always be a bit more risky for players.

Long-term, one of our principles is that creators should be able to do almost anything we (Mojang) can do with the Vanilla game. So that's pretty extensive customization. But this is aspirational, and it'll be a long road for us to travel down together here. We'll release incremental features as we go.

Which parts are being favored first? I think that's being discussed in other threads.