Lavaflow

This datapack is still in beta. Future (and frequent) changes that cause chunk borders in existing worlds are likely. Use at your own risk

Lavaflow completely overhauls the nether.
Instead of the random noise of the vanilla nether, Lavaflow features specifically crafted terrain, like you are used to from the overworld - but way more 3d.
Biomes are placed not at random but in places matching the terrain.

You can view a map of the biome distribution, terrain, and structure locations on map.jacobsjo.eu.

Find the high elevation lava rivers among crimson and warped forests. Among them some warped forests have grown older and taller then ever before.

Follow the rivers them down the lavafalls into canyons and valleys.
Among the soul sand valleys, a new forest is thriving (?): The Ghost Forest.

Follow the rivers further to their mouth into lava oceans: Vast areas of lava overlooked by narrow layer above, on which the nether forests have ventured onto. Massive pillars support the ceiling. Legend has it that they were once of high demand with miners.

Where there isn't a valley or ocean, you smaller caves take their place.
These seem to have formed more recently and might expose what is otherwise well hidden.

The vanilla structures tie the terrain together. While almost unmodified in structure, their placement is chosen to enhance the terrain. This includes different placement for each Bastion Remnant type.

Beta:

This datapack is still in beta. Especially, I welcome feedback on ore rates and structure frequency. I might also add more biomes and structures before the full release.

Additional notes:

The base block is changed from Netherrack to Smooth Basalt. This allows for more interesting columns and walls, but this has a few gameplay effects:

• Floors and ceilings are usually covered with a thick layer of Netherrack. Netherrack blobs also exist underground
• Gold Ore can be found in both Netherrack and Smooth Basalt, turning into Deepslate Gold Ore in the latter.
• Quartz Ore can only be found in Netherrack, making
• Mining for Ancient Debris is much slower since Smooth Basalt is much harder than Netherrack. To compensate, Ancient Debris is more common and has a more interesting distribution.