Griping about D&D made me think. One of the main elements I like about a system and setting is the "Kitchen Sink" factor. Really fleshed out worlds give me as a GM enough play things to grab onto and build an adventure with out overwhelming me with 'you game must be this'. In essence it's a blend of crazy huge setting, detailed back story, and a writer/developer understanding enough to let me break their toys when I use them.
My most favorite Kitchen Sinks:
Shadowrun's Earth (Ya Chummer I sent out of Seattle in my games. CallFree baby!)
World of Darkness
And these are just he published ones. I often would create my own Kitchens sink settings like my Final Fantasy and Ninja High School inspired games during college.
One of the joys of D&D 2nd Edition was all the well developed worlds. I think that's what TSR did right, they build world and gave enough specific toys to let the players go explore in them. What they and WoTC did wrong was fill these settings with too many god NPCs and world metaplots from the various novels, etc that it bogged down the enjoyment of players who liked the raw but heavy setting that was given to them. I call it the Forgotten Realm effect. FR is a Kitchensink gone wrong. It's what happens when the creator doesn't let the players drive the plot. Something you may notice in the Golarion Pathfinder APs is the players can very easily rewrite huge parts of the world (take over a nation, estabish a free nation state from devilish control, unlock secrets of the lost past, etc. World shaking, campaign world altering adventures. But when you pick up the next AP the events of the prior are optional.
They called this the not-quite-a-meta plot from the days of Exalted 2E. You have to have setting hooks to get a player and GM interested. Let's talk 13th Age a second. Mechanically it's interesting, I like the system and it's hybrid 4E/3E D&D logic. What I don't like is the setting. The Dragon Empire is TOO trope tastic and iconic. Worse, if I wanted to ditch the setting I could, but there isn't anything out there (yet) interesting enough with unique powers, ICONs, and backstory to get me to want to play it. I think Monte Cook got it right with the amount of backstory fluff in Numerera. While I may not entirely like the way the GM intrusion system works, I've got no issues with the 8 prior worlds, the vast earth like world and the strange elements of the setting. (With maybe the childish evil monster baby making golem things people are throwing a tizzy about recently.)
When I cook up my own worlds I try to build from strangeness outward. The core element the PC's need to enjoy is the ability to be unique in their own way while having enough stability in the surrounding setting to contrast against. After all, if the ENTIRE world is ninjas and super heroes, what's the point if you are a super ninja? I call it the Saints Row effect. The early games the main character was the extreme example in the game, but as the series went onward the whole world got progressively wackier. What was the point of the Saints when you fight aliens, government super agencies, and luchadores using grenade launchers.
Getting the right mix of kitchen sink OPTIONS with stable environment is the key. Even settings like Eberron and Exalted have consistent internal rules for how the world works. The players break the boundaries and introduce the chaos the setting needs. Well, them and the main badguys.
So next time you are playing a kitchen sink game just remember, where's the fun? You're soaking in it!