I wish they'd double it to 256 height. And place the sea level at about 96 or 128. I'd even love 512. They'd just need to figure out how to do "vertical chunks".
Another thing I'd love to see is a redone Nether. Instead of having the Nether for fast travel, because really, it's a boring concept when we have super fast carts, I'd love for them to have the three dimensions stacked on top of each other with seamless transition from one to the other. The Nether would be below the real world which would be below the "heaven world", or "sky realm" or whatever they were thinking of doing.
Each one would be generated itself, and only when the player(s) get close enough to generate them, but you'd be able to dig all the way down to hell, or climb all the way up to heaven. The clouds would be at the 128 block height and hell would be at 0.
Portals would no longer be for fast travel, instead they'd simply create a matching portal in hell below. And there could be a secondary portal called sky portals which would instead take you to the sky realm. (Maybe they'd be made out of Lapis blocks instead. Which would mean they'd have to make that stuff more common)
It would be seamless. No loading. Instead the world would be divided up into 64 high chunks and it would load 2-3 at a time depending on where you are vertically.
) to link the old spawn & the current spawn, as well as any major cities/towns in the new spawn area.
