Developer in need of ideas

Something like factions could be difficult to pull off given there can be multiple levels in the nether. Something economy based was my initial thought on the concept - finding certain ores, selling them for stuff worth money, having things like diamonds worth a ridiculous amount...

You're in a world with custom generated sky islands, maybe even different biomes, and you ofcourse have to survive like in skyblock but you can also build to other islands and claim them. Every island has its own core. You claim an island by claiming it's core. When you've claimed the core it has a certain amount of power. Every time you die, the core loses some power. The only thing that can restore the power is (diamonds or something). This adds a factions-like fighting element to it.
Some extra ideas:
1) An economy system, you can buys and sell stuff (Only if your close to one of your cores?).
2) You can get diamonds every certain amount of time.
3) All cores lose power when you die.
4) Backpacks, chestplates that can store items
5) When you are offline you're a killable npc with your skin that is laying down.

I could totally see a faction type gamemode with skyblock elements (where you have to do interesting things to get certain items).

I must admit, a server totally built around the nether would keep me in for a while if done correctly.