A suggestion that hasn't come to pass yet, nobody I've seen openly disagrees with the idea of cubic chunks becoming part of vanilla Minecraft.
Mojang is refusing to listen to what happens to be one of the most popular suggestions ever put forward by the community, and for what? it wouldn't break the game to remove the 256 block height restriction, it wouldn't spoil anybody's fun if this were to become a reality for vanilla Minecraft both Java and BE.
Who is going to care enough to complain to Mojang about mountain tops generating at 380 blocks instead of around 110?
who is going to complain about bedrock no longer existing at Y 1 and 2? no one, most people would view it as an unnecessary restriction they'd rather be swapped out for deeper mines. The void isn't accessible in the overworld in survival anyway, you have to be in creative to break bedrock, or tamper with your world. But the void is useless, so who cares.
Edit: I'd also like to add most ideas have downsides to them, as well as upsides, this one doesn't appear to have any downsides, other than development time, and the fact it requires a mod if Mojang doesn't intervene and sort this out and stop artificially limiting people's creativity.
Cubic chunks with a few tweaks could work for survival play, even in bedrock edition.
it's just that at the moment you have to play an old version of Minecraft java with a mod to have this feature.
and in 2019 this is beyond insanity, I've actually considered not playing the game anymore because of this, it has killed my desire to play the game more than anything else.
One reason: Mojang is lazy.