What's the difference between crap fluff and good fluff?
Well, a good start for a working definition might be that crap fluff is anything that a pair of satirists come up with in order to construct the worst possible name for a location in a fantasy setting.
That WotC hit that nail squarely on the head is quite a vindication for those of us who have been criticizing their ability to construct proper nouns for the last few years.
Can you list some example of good fluff for comparsion?
Walking into the obvious trap, how about:
Anything by Ari Marmell, most of Planescape, a decent amount of the Storyteller games, a lot of the stuff from the early D&D modules and supplements--particularly the stuff that has remained in the general consciousness over the years.
A good way to tell if something is good is to look at whether it has stood the test of time. Good versus bad is not an objective measure, but rather the aggregate of the community's subjective opinions. However, it's not that difficult to get a grasp of whether a given idea is going to work well, based on what has worked in the past.
With respect to WotC's NounAdjective naming conventions, the only successful example from the past that I can remember is the Underdark, but that seems to be an isolated case. Indeed, the NounAdjective naming convention has generated so many ill-conceived names for so many writers over the years that Penny Arcade predicted (successfully) that its readers would understand what they were parodying with the "Further Songs of Sorcelation" series. I think that it's telling that WotC not only did not avoid NounAdjective names like the plague, but embraced them as company policy, apparently not aware of the negative public attitude toward them that Penny Arcade has capitalized on.