Well it look like I am going to be running some 5e, with that in mind I have been doing some world building.
Grimm and Gritty:
This is a world where even relatively minor wounds can cause great difficulties and where healing magic is miraculous and rare.
Local Heroes to national movers and shakers:
The heroes will be given the opportunity to find, claim and restore an abandoned keep. The challenges that they will face, will be best overcome by them becoming local figures of power, such as religious leaders and nobles.
This is a world where the choices of the adventurers will shape the course of first their community and later their nation. As a way of facilitating this aspect, the setting does not have alignment the only judgement as to the morality of their actions are their own perceptions, and those of the world around them.
Three faces to the world:
In most DnD settings the physical world is the entire focus, and even the feywild and the Shadowfell take a distinct back seat. In this setting, the Feywild and the shadowfell are going to be as important to the setting as the physical world.
Passage between the physical world and either the feywilds or the shadowfell is common enough that it is a regular activity even in the local tier for adventurers
The shadowfell is especially important in this setting, for it is the first stop made by the spirits of the denizens of the physical world after their death, as they make their way to the labyrinth and their eventual reincarnation.
The art of magic item creation is held only by a few powerful denizens of the feywild, meaning they are incredibly rare. Moreover the denizens of the Feywild have almost no interest in the riches of the physical world, and when they do trade or gift them to the people of the physical world, these items come with oaths, geases and curses which bind them to a single owner, all of which mean it is practically impossible to buy and sell magic items for gold coin. That does not mean they cannot be bought however. If you can steal a maiden’s voice, or have access to a hanged man’s hair, or if you will swear never to turn down a request for aid lest you suffer a terrible curse, you may be able to purchase a trinket or treasure at the goblin market.