If you are talking about a video game the closest I could see a Dark Sun open world game coming is an Elder Scrolls game. More than likely Elder Scrolls: Hammerfell.
It would be cool to see the Tyr region in an open world setting, but that would be a major undertaking. In particular I'd enjoy seeing a living world were trade caravans go from city to city and monsters are actively roaming the desert. In particular Defilers would create a radius of death around them that could kill their companion characters if they arent careful. Everytime a major spell would be cast a black radius of death would transform that spot in the world permanently.