When you rework Alice in wonderland, do you start by saying, "Well, there's no Cheshire Cat, no Mad Hatter, no Queen of Hearts, and Alice walks not through a fantastic world but a blasted plain...," and expect someone to think that you are playing with the original Alice themes interestingly?
I was reading the original post as more of a "Well, the Queen of Hearts and her retinue aren't actual playing cards come to life, but rather a human kingdom that uses playing card suits as their heraldry, and the Cheshire Cat isn't a cat, but rather a vagabond minstrel who named himself after a feline, and the Gryphon and the Mock Turtle are titles of knights who use fantastic beasts as heraldry, and so on." There is a Drizzt (or was), but not a literal one. There was a Bruenor. Elminster is around, but if you visit Shadowdale you find he's "simply" a very well-learned sage.
The thing that makes the Forgotten Realms even more appropriate to this is that they still have a lot of "characters" in the form of geography: nations, ruins, woods, deserts, etc. Waterdeep is still a character. The religions are the same. There's a lot left of the Realms even if you turn the 11 back down to a 3 or 4.
Do you start describing an Arthurian retelling by saying you've removed Merlin, Mordred, and Morgan le Fay?
You could, particularly if you're trying to avoid the feel of predestination or if you're pitching a low-to-no magic or "historical fiction" game. In fact, Arthurian retellings go all over the place: admittedly, the recent King Arthur movie is one of the poorest, but its flaw wasn't the absence of actual magic or the Morgause/Mordred subplot, it was the absence of the big fatal love triangle. The Mabinogion's very Arthurian, and it lacks at least two out of those three characters.
Would it be an Arthurian game for people who really love the high-magic approach to Arthurian legend, or whose favorite characters are the magicians? No, absolutely not. But it could still be called Arthurian, and specifically a retelling.