I discussed the death of the heavy setting some time ago. While I dearly love the effort and care that goes into the heavy setting, and put more than a few on my shelf, there is ultimately a reason I don't generally use the full breadth of them. Because that's the point. Really you jump off and build your own setting. Your own rendition. Loving Scarred Lands doesn't mean memorizing 35 books so that you can recall every incidental thing of every single area and culture described. You essentially like the overall vibe, and have resources to delve into any specific area if you want to. That's the point of a published heavy setting that's been lost of late. You can literally play Harn with just the Harndex and/or Harnworld.
I recently procured World of Greyhawk and City of Greyhawk. I'm vaguely aware that these are from different time periods in the setting. That being said, who cares? Basically Greyhawk should not be beholden to canon, nor should any setting. The strength of Wilderlands of High Fantasy is pretty much anything makes sense there. Greyhawk is similar in a way, it presents a fairly standard fantasy world with some traditional conventions that make it THE standard AD&D world.
Good settings, including heavy settings, give you the room to make it your own. Those that don't, aren't good.
So why disparage the light setting where you can effectively "make it your own?" Because you aren't given an option. You MUST make a light setting your own/do the gruntwork to build out all the details and hope they end up making sense. Having an element to fall back on is important for judging a work. A work of fiction is usually an outline fleshed into something with effort. Getting handed an outline is meaningless and worthless. Same goes for settinngs.
