Of course, the problem is making that all work under the context of a power-scaling group dynamic Game.
Aspects like localized baddies, sacrifice and loss, etc is very hard to do in a game where four or more players sit around, eating Cheetos and quoting Monty Python. It's the same reason why horror in RPGs tends to be very different from horror in other media; a lot of the core defining tropes (weak protagonists, isolation, escalating body count) aren't well suited to reoccurring character group play with power accumulation.
So you end up stealing the wallpaper of the genre, not the structure. In horror, D&D steals the spooky castle and vampire lord, but it can't recreate the visceral fear of Harker locked in Dracula's Castle. The same is true if S&S; you're barbarian can look like Conan but he can't be the invincible slab of meat going against overwhelming forces playing out a rather intimate tail of revenge. At best he's a strong warrior fighting a giant snake monster.
Which I guess is to say that in the context of RPGs in general and D&D in specific, the GAME elements have to come first. You still design for the fighter, cleric, wizard and rogue, even if they are all wearing loin clothes and sandals. You can't beat D&D into confirming to the genre tropes without it breaking somewhere. So the best you can do is give it a gritty sand-covered coat of paint.
Which, bases on the original premise of this thread, is all an official D&D S&S setting would do. No low magic, rewritten classes, or radical overhauls. D&D with a taste of the S&S flavor. Anything else requires more rewriting than an official product would dare and probably is needed.
