Each world should have a hook. A big idea that sets it apart.
This one is the world revolves around the 7 Virtues & 7 Sins. Not sure I will even call them that, but I am going to have 7 opposing concepts that govern everything.
No alignment, but in place of this will be tracking your position on 7 trackers. (I did something similar for Kage ages ago).
I have ideas for extra features like BGs in Ravnica as well as organisations there. So as you make your way towards Generosity (for eg) you get certain boons along the way. I will also include drawbacks too.
I have so many ideas around these 7 opposing forces. There will be patrons/exarchs of each force. These will serve as the 'deities' of the world. Divine magic will be based upon these forces. I might even make ALL magic inherent on them and sort spells into lists based upon these forces rather than class. Or I will keep it simple and just add domains for each ;) (But I really want to do a setting with spell groupings done by something other than class). I have 3E domains for both. Pathfinder also had some 'sin magic'. I can't remember what that was, but might look into it. :)
So, I don't even have a physical setting in mind yet. Ideas welcome. What do you think of the hook?
So, your PC will try to be a paragon of one (maybe a few) virtues or sins. There is so much design space around this.