I used "boring generic" to make it explicit that I know I am a crotchety old man
I agree with what [MENTION=82284]ceiling90[/MENTION] is saying, though I would say that it is a very similar concept to expansive, but a little different in some of my personal experiences.
The Swordcoast and Nentir vale are generic areas. Pretty much stock standard fantasy. Nothing wrong with that. You can throw in an Arabic sea trader without breaking the world. A travelling Oriental diplomat will fit in just fine. Pretty much any plot and monster can be used seamlessly, even without extensive travel. It is generic and expansive, you can dip into gimmicks for a session or two, then move on.
I created a world where each area was very heavily and strictly tied to a mythos. So there was the Egyptian area, with mad sorcerer kings making necropolisis, the dragon emperor of China, the Celtic wilds, a transylvania area, a Norse area, a Spanish queen recruiting people to discover the Aztec area etc. This was a collection of 12 different gimmicks, as opposed to making an expansive generic world. Adventures, monsters and themes of one area did not translate well into another. Sure there were interactions between them, but the themes were strong enough and localized enough that it was not a generic world. In each area, I was restricted in what could logically happen there. This is unusual of course, but I could see a similar thing happen in any world where you put the themed areas outside of practical reach and don't use them as a splash of colour regularly enough.
Taking FR as an example. I would go out of my way to have their captain for a voyage on the Sword Coast be a guy from Kara-Tur with a Junk ship, just to remind them that the place exists. The guy that runs the local alchemist has a strange last name as comes from Al'Qadim. When staying as guests of the duke, there is a very touchy Samurai guarding the guest quarters next to them, not allowing them anywhere near it. Just occasional things to make the world feel smaller.