How a 5e-specific Campaign Setting would be?

[DragonSorcererX]

So, how would be a Campaign Setting that uses D&D 5e assumptions and mechanics the same way Eberron used the 3.5 ones?

[Connington]

You could do this, bit I don't think the results would be very distinct. Eberron worked because the 3.5e rules assumed a high level of magic and a ready availability of magic items that wasn't consistent with a medieval setting. 5e makes much more conservative assumptions.

[JAL_1138]

The 5e campaign setting would be a dead, barren world, devoid of all life. All it takes is one mad wizard with Simulacrum and Wish in their spellbook, a poorly-worded instruction to the first Simulacrum in the chain, and the planet starts filling up with Simulacra in a "Grey Goo"-style apocalypse. The chain of replicating Simulacra ends when there are so many that they either crush the last one under the weight of the trillions of Simulacra covering the planet's surface, or the tide of Simulacra builds up so far that the last one is pushed up on the flood of bodies so far above the surface of the planet that they can no longer speak the verbal component of Wish due to lack of atmosphere. Eventually the Simulacra, now the only "living" things left, will die off from various causes (since they apparently don't heal naturally), and the planet will be dead.

[DragonSorcererX]

The 5e campaign setting would be a dead, barren world, devoid of all life. All it takes is one mad wizard with Simulacrum and Wish in their spellbook, a poorly-worded instruction to the first Simulacrum in the chain, and the planet starts filling up with Simulacra in a "Grey Goo"-style apocalypse. The chain of replicating Simulacra ends when there are so many that they either crush the last one under the weight of the trillions of Simulacra covering the planet's surface, or the tide of Simulacra builds up so far that the last one is pushed up on the flood of bodies so far above the surface of the planet that they can no longer speak the verbal component of Wish due to lack of atmosphere. Eventually the Simulacra, now the only "living" things left, will die off from various causes (since they apparently don't heal naturally), and the planet will be dead.

At least it's not like 3.5 where one character could reset the universe and other could become a dragon god and create his own universe, and all of this by RAW...

And if you want to stick to the Core, a CR 3 Undead could kill the Tarrasque...

[Grod_The_Giant]

Confusingly, given the lack of real rules for NPCs.

[comk59]

I would say that the land would be a hostile place, filled with an endless tide of Shadows. The only safe places would be in brightly lit cities, and in the sky.

[Regitnui]

A more grounded version of Nentir Vale, a place that could be plucked out of or placed into any campaign setting with no distinguishing features