Personally, I think that a really good Greyhawk style setting, but one that isnt Greyhawk, is needed. the FR is to crowded with scarily powerful NPCs, Greyhawk has no support, Kalamar and the Scarred Lands are both good, but a bit to different for my tastes. I'm not really into the whole Titan thing, or the alternate classes. Dragonlance i'm, well, I think it would be hard to do, because the books really didnt flesh out anything but the central group, and even when they did, most characters would pale in comparison to what was going on around them.
What I want is just a generic fantasy setting, or more support for greyhawk. Even just a core book, like the FRCS book, would be great. I mean, i homebrew a lot of stuff, but most of my campains lack the kind of unity afforded by a core setting book.