Usage of new build height and rework of Y coordinates.

It's not escaped our notice that it's now possible to change the world build height with data packs. I hope that a full 1024 block build height is taken advantage of. A full 1024 build height can strain some computers so it would be nice to see options for different build heights at world generation, Personally I'd like the options to be 1024, 512, 256, and 128 for old times sake.
Now what to use all this build height for is somewhat obvious with the update title, soaring cliffs and deep dark caves.

I would also like to see a bit of a rework of how the y coordinates work, I've been playing minecraft for a little over 10 years by this point and I still can't name sea level off the top of my head. What I'd like to see would be sea level place at y 0 and the height of the tallest mountains at about a third of the build limit above that, splitting there world into a third for underground a third for surface and a third for sky/ so for instance on a 1024 build height world y 0 would be 342 blocks above bedrock. The top of the highest mountains would be an additional 340 blocks above that at y 340 / 682 blocks above bedrock. This leaves the world max height at y 682 / 1024 blocks above bedrock. This means that you have 340 blocks of navigable surface terrain, 342 blocks to build up from the highest peaks, and 342 blocks to build down from the shallowest plains.
256 worlds woulds remain unchanged generation wise but there would be an option to set y 0 at sea level.