The stuff I loved most about Al-Qadim really wasn't setting-specific. It was more of a stylistic thing, where the adventures encouraged storytelling and NPC interaction instead of 'gruff stranger hits you up in a bar to go clear the caves of ker-chunk.'
In a setting, I like a certain amount of versimilitude. If the world has magic, as pretty much all D&D settings do, then the world should have been visibly affected by the presence of magic. Forgotten Realms touched on this with the presence of portals and gates, but it was Eberron that really opened the floodgates and envisioned a world where magic had societal repercussions every bit as world-changing as the invention of the stirrup or the germ theory of disease.
I prefer 'less is more' for races. I'm willing to allow all of the standard PC races, but once we get into the humanoids, I start finding ways to consolidate them. In my Freeport-in-Greyhawk game, the Valossan Serpentfolk are a pregenitor race from which the Lizardfolk, Yuan-Ti, Troglodytes, etc. all have degenerated. Hobgoblins, Bugbears and Goblins, like Elves and Gnomes, have fey origins. There may only be a few known dragons, each a legend in it's own right, and the notion that they are *species,* and that there could be multiple 'red dragons' is just crazytalk. (Limiting dragons to just five or so, each an Adventure Path worth of adventure in it's own right, and skipping the 'good dragons' entirely, fits my tastes better.)
'Less is more' also fits best for dieties. Huge pantheons become unwieldy, and no matter how much I love Roger Moore's demihuman dieties, I prefer a Dragonlance/Kalamar-like setup where different cultures have different names for the same gods. Ideally, smaller pantheons, like that of the Scarred Lands, suits my tastes, with the various dieties having pretty wide-ranging domains, so that each can support multiple concepts.
