Over the last couple of years, I’ve come around to the opinion that Forgotten Realms was actually a good setting. Back in 1st edition. Things clearly took a wrong turn with 2nd edition when it went all ultra-twee, and the setting got brutally mangled in the general D&D design overhaul of 3.5e. And then it got all blown to gory chunks in 4th edition and only continues to exist as the background for big adventure books without ever having gotten a new update through setting books.
Now, obviously, there is absolutely nothing at all to indicate that the next edition of D&D will somehow include a revision of the Forgotten Realms that salvages what was originally great about it.
But if I were to make the decisions for future Forgotten Realms sourcebooks…
This is what I think should be done:
Since generic default D&D has pretty much been Forgotten Realms for the last 35 years, there really isn’t any need to have a player book that covers the setting specific races, classes, and magic types of the setting. Just use the PHB content as is. Setting specific material should be covered in three regional books: “Sword Coast”, “Heartlands”, and “Unapproachable East”. I think this would cover everything that 98% of all Forgotten Realms fans would care for. I am not saying that nobody has ever played a campaign set in Tethyr or Mulhorand, and in some four decades it surely must have happened once or twice. And while I would actually predict a big outcry that there need to be two or three more books to cover the rest of Faerûn and that those books might even sell somewhat, I would think that barely anyone would ever actually use them to run campaigns. Just have a page in the Sword Coast book dedicated to “Lands of the South” with information on how to make and run NPC merchants from Amn or Calimshan that are visiting ports in Baldur’s Gate or Waterdeep.
I personally think the three books should also describe the regions as they were before the Times of Troubles, but I have no clue how I would try to pitch that to the bosses to get an okay for it. It absolutely would hurt sales. But it really should not be set any later than the point described in the 3rd edition FRCS. The metaplot just got really dumb after that.