Eberron, because it is close enough to modern to be relatable to a general audience while retaining plenty of fantasy elements. Plus, it's literally built on the back of pulp fiction stuff, which remains highly popular today.
I also voted Nentir Vale, mostly for a reason I think a lot of people here will overlook: it has, by intent and by accident, no baggage. There's no massive expectations that it be any one specific thing. No enormous history of specific elements. It's highly playable, and thus highly writeable, and it's not going to get torches and pitchforks mobs with every other decision. The freedom to make the show one wants to make rather than the one the persnickety fans demand would be a huge boon.
Finally, something you didn't mention but which would be amazing: Iomandra. It's practically tailor-made for an episodic format, what with the zillions of islands. The nautical/pirate theme is also popular, and dragons are always in style.
Those are my votes. Dark Sun would never make it outside of "prestige" TV and even there it's a bit much what with the genocide. Many of the others are either too niche, too weird (Planescape, Gamma World), too historied and thus massively overloaded with fan expectations (Forgotten Realms, Greyhawk), or too full of racialized implications (Kara Tur, Al Qadim, Maztica) to work.
If I picked a fourth, it would be Spelljammer, as it has similar benefits to Iomandra. If pressed to pick a fifth, Dragonlance; although it has a ton of expectations, it's also got the core novels and the "play these novel sourced characters" element that could be used to justify a "War of the Lance" TV show that could work out okay. It would still labor under a mountain of fan expectations but they would have that core narrative to guide them.
I genuinely do not think any of the others would be viable.