After running LFR as a TO and judge at my game store for the last few years, I've decided I want to do something different: Living Dark Sun.
There are a lot of elements to recommend it.
First, Dark Sun doesn't have the vast bulk of FR lore behind it, which makes it easier to adjust for new players. Speaking as a long-time FR player, I know I find it frustrating to have players who don't know the lore and theme of the world (and I know they find it frustrating when I start off on one of my thematic tales of how thus-and-such fits into the universe of FR...and their eyes glaze over...). While Dark Sun DOES have a lot of lore, it's from a long time ago, and few people are still around who played back then or embraced it.
Second, it's an exciting, fast-paced world filled with roleplaying opportunities that are different from any other game out there. FR is a "classic" fantasy world. Its communities and societies have strong analogs to many classic medieval and modern societies, and it provides a great deal of RP opportunities, no doubt--but it's also so vast and broad that it all sort of blurs after a while. Travelling from Cormyr to the East Rift to Waterdeep to the Dalelands from module to module causes things to get jumbled; the storylines, while good, are rarely run in order for the characters and as such, grasping the Realms is often like a whirlwind tour of all the countries of Europe where you spend 4 hours in each one. Eventually, Germany feels a lot like Austria feels a lot like France, and you don't have the opportunity to grasp the nuances and things to appreciate about each one. Dark Sun isn't monolithic, but there's less there to have to absorb...and it's fresh.
Third, it's a very challenging world. Magic is rare--hell, even METAL is rare; the divine doesn't exist; the environment itself is deadly and the atmosphere is a lot more points-of-light than the Realms are. Characters are fighting for their very survival in a grim, gritty world; their successes may not be epic but even the low-level opportunities will have a sense that you've truly accomplished something of meaning.
Fourth, by its nature, it is more restrictive of races and classes than LFR is. I love the fact that in LFR you can play pretty much anything, but I also see the appeal of having a limited pool of classes and races to play--you don't have to devise a reason why a Kalashtar, a Shardmind, a Githzerai, a Minotaur and a Drow are being called upon by a predominantly human ruler of a country to do a job. Because there are fewer races, they have more visceral ties to the world and the universe; and because there are fewer classes, they have more ties to the game world.
Fifth, the themes are beautiful roleplaying hooks; factions in which the PCs can definately get their RP on.
Sixth, the combats will certainly be challenging regardless of level. The game is supposed to be challenging--and deadly. Raise Dead and Ressurrection aren't going to be easy to come by, so risks are going to be very large in this game and characters will be a lot more careful about what they do.
So I'm developing a Living Dark Sun campaign. I'd like to do it under the auspices of the RPGA, acting as its global admin, but if I can't do that I'll do my own privately, and invite others to participate. I'm a game store owner; I've got a vast number of RPGA players and judges to work with, and I'm open to volunteers to assist and help.