This mod was designed as improvement for the Nether, adding more biomes, plants and materials into it. I've tried to make its content unique and interesting for exploring as also useful. Many concepts are still in WIP, but here are some results, that I have.
Mod was designed as compatible with other nether mods (especially in world generation). For other desirable compatibilities please write on issue tracker.
Primal things, that this mod adds:
1. Many new plants to the nether;
2. Non-vertical volumetric biomes;
3. New materials, recipes, food, tools and items;
4. Ability to farm some materials using plant farms;
5. Many nether structures, including big and rare cities;
6. Ability to configure presence of blocks, items, biomes and plant density.
Here are some screenshots:
Full description is here: Minecraft Forum (including development log and current stage)