I have more to my space idea! Haha! This is a much more detailed, including a steel phoenix, guide to SPACE(Time)
Space, as explained in like 50015 pages ago, is a gravity-less (Other than the planets, or rather portals to a planet sub dimension...)
empty abyss with random spacerock/iridium ore patches of blocks (Iridium is common in space, do your research! XD) and planets- which is surrounded by invisible portal blocks, that act like end portals, but transport you to a planet sub-dimension! There will be 5-9 planets (Cant decide XD), which will be close together, and a randomly picked 1-2 stars, which will set you on fire... a steel (NEW Block) moon (Other moons are still small, but dont have any use... ) will be on a random planet, with a portal, sending you to the space boss, a robotic phoenix.
The robotic phoenix will attack by slamming you with his feet and shooting plasma at you, and you have to kill him by destroying his smaller phoenixes then brutally killing him, with a diamond or greater sword. Then he drops a portal to the Overworld spawn.
The portal to get to Space is crafted as shown below.
1. phobos has tried and failed as A. you cannot hack a mod, and B. he failed at trying to 'create conflict' between us and a paraelle yet completely different mod, FOD
2. We have pre-alpha versions, but no official versions out.
And jakest, we dont have them coded because you never gave me a link to get ay of the models!
EDIT; nvm it seems you snuck them in without me noticing...
I have an idea for the Nether boss. You see, instead of fighting a single creature, the Nether ITSELF is the boss. The core of the Nether seethes with anger, and once you travel to the core, the core will start fighting you by throwing chunks of land, creating lava fountains, sinking the islands you're on, You fight back with snowballs and TNT dropped into the lava. After a while, the core's soul will be destroyed and the core will return to normal.
But here's another idea for all bosses except the Enderdragon- the bosses can get one last extremely deadly shot off on you. For example, the Core will, in its last breaths, cause the lava level to start raising. And fast. So you have to run up the core's platforms to get out of there before you get toasted and the core explodes before going back to normal. The Sky Knight might cause a massive hurricane. King Neptune or whoever the Abyss's boss can cause a vortex which causes a whirlpool and other obstacles for you while you rush to swim to the surface to return to the Abyss's main world.
Oh, and while I'm here - how about an electric world, maybe industrial called the Wastelands as the overworld's side dimension, possibly to have one for the past (The Crypt) and one for the future (The Wastelands). Explosives, redstone, lightning, factories, pollution, lots of clouds, storms, wastelands, traps, more lightning, and an atmosphere that's devoid of life but the difficulty is made up for in the fact that there is toxic gas, traps, and electrocution hazard/ Oh, and breaking blocks will be limited in order to prevent trap disengaging.
Just an idea, there could be a "distorted" dimension where the mobs skins and ability are randomly swapped around, you would have a zombie shooting arrows while a cow climbs a wall to poison you, all while a silverfish is shooting ghast fireballs at you.