I don't particularly like the FR but will be buying it anyway when it comes out. Sure once Greyhawk or Planescape come out my game will switch but till then it's FR.
I like to create adventures but HATE world creation.
If it was the 3.5 FR setting or the altered 4E FR setting ...it wouldn't matter to me. Just give me something I can bolt my adventures onto and away I go.
Now a Greyhawk or Planescape would excite me in ways FR doesn't but that is just personal taste. I really have zero clue why people even care THAT much about a official setting and the changes.
After about a year of play my home setting always WILDLY differs from the official ones anyway.
A year from now Waterdeep might be destroyed, Neverwinter might be the occupied by Evermeet and Cyric might have killed off a couple more gods. The spellplague might be discovered to be a sentient creature and Ancient Undead Hordes might be raising everything in the north as a Ancient Lichking rises.
Shrug,just gimmie a basic framework and Voom Voom!
1) When it first came out, the Forgotten Realms had a certain depth that I hadn't seen before. Very organic, not (too) haphazard. It had been worked on polished smooth before getting picked up by TSR. Sometimes the information provided was in overload mode (seriously how many paragraphs on 'nutty/salty' cheeses and pickled eels do we need?), and it's been around long enough to where some subpar supplements or ideas were thrown in, but for the most part FR earned its fans. That's why people care.
2) You make a good point about the utility of published campaigns--just good enough to bolt an adventure off and there you go. OK, fair enough. It's fie being of that frame of mind. Some of us want more, although it's not for the campaign world you really like.
3) The game play (or 'campaign play', whatever) of each setting is different. The World of Greyhawk is smaller, has various developed nations butting right up against each other. More magical medieval plots afoot, etc. etc.The Realms is a bit larger, spread out. Some areas where that style of play can happen but more city-states and wilderness. Planescape, of course, is a flavor all its own. A gateway to every plane imaginable, and the artwork really evoked the differences...
3) Waterdeep destroyed, Neverwinter, more god-killing, etc....ummm WotC is going to shy away from anything like that. If it approaches Realms Shattering size it will be squashed. The readership already made it known how sick of it they were. (Loss of business = "QUIT breaking stuff and telling us it's an improvement! It is not. A mistake is NOT a feature!") In all seriousness, FR designers and writers have 'broken' just about everything, especially demihuman nations and strongholds. It's annoying. The Realms will keep spinning, things will still happen, but the designers are going to refrain from hammering a spike into the fans' hearts every time it turns.