This mod idea came to me while looking back at my favorite biome mod, Biospheres, and the idea is this: A mod that duplicates every non water biome and generates floating islands in the ocean using the copied biomes.
Bysically like: "Sky Plains" "Sky Mountain" "Sky Taiga" etc.
Allowing players who explore oceans a lot a chance to find new land in the sky above large open waters where they can build homes or pillage dungeons, or use creative mods or build ideas to create better and creative game play experiences.
I'm not saying build a mod that makes a random floating survival island for challenges or what not, but a mod that creates new biomes to generate large floating land structures above ocean space within the already available mine craft world generator.
This could fill ocean space with floating islands that can range anywhere from 10 blocks off the ocean level to 100 blocks off ocean level.
This mod Idea is something I haven't seen anywhere but on a minecraft concept art/artistic poster/T-shirt design before.
The idea removes the need for the Nether portal while playing the game by making it much more difficult and dangerous to reach the nether.
Generating the nether space far underneath the everyday minecraft world allowing navigation within the nether and also making players pay attention to the sounds and level at which they are mining at.
Potentially using a vertically registered biome for the nether so that nether mods only spawn within the nether space under the natural world, and also allowing variations of iron, redstone, and diamond to be found in the nether.
Also potentially introducing fused blocks between netherack and stone for a different substance altogether for players to mine out to get into the nether, moving the world build height much further or by introducing negative height to the game where players can enter the nether from.