I can't recall a fantasy media thing that feels like the forgotten realms in a long time.
Harry Potter
* aside, If you look at the Fantasy that has broken out into the mainstream, you have:
Lord of the Rings, Game of Thrones, Conan, and The Witcher.
All three taken individually, or heck, even combined are far and away more "low-magic", and less fantastical, than Forgotten Realms ever was. Or core book baseline D&D for that matter.
You don't have to throw in the kitchen sink to make a fantasy setting compelling, and adventure worthy.
*Kids fare will naturally be more whimsical by default.
If they deviated hard from 5E and did a sort of E6-ish thing I could see it working but the OP's position is that they don't.
^This^ And I don't think a E6 or even E3 play model would be that hard of a deviation.
And, he did say:
I see some wiggle room there!
Part of why D&D doesn't work for some fantasy genres/vibes though is its use of linearly increasing HP.
Plenty of RPGs which either have HP that don't increase linearly (in some cases don't increase significantly at all after chargen), or don't use HP at all are as fun or more fun than D&D
In fact, I'd go as far as to say it's one of the things that people tend to end up disliking about D&D, and it's one of the many reasons so many campaigns peter out in the 8-12 level bracket, because HP have got so crazy. It's also why in editions where people have low HP at L1-3, adventures often have to be written in peculiar ways to "shepherd" PCs out of that zone, and why, as far back as 2E, starting L3 seemed like a good idea.
I'll go further and say that making d20/5e based games around an E6, or even a E3, flat HP paradigm is a big unexplored design space for d20 games that even the OSR has yet to dive into.
5e's 'Bounded Accuracy' based math would be a good base for this. And the Dark Souls RPG, even though a bit DOA, did show that there is enthusiasm for a 5e variant that is willing to redesign itself around a different paradigm of play. A E3 fix HP fantasy game would play out very differently over time than the current HP to 20 levels 5e model.
If WotC does a Gamma World or Star Frontiers style game; A fixed HP model should be embraced.
Which of course means that neither will ever happen. I just cannot see WotC doing a5e based game that doesn't work
exactly the same way as their D&D offering.
I'd be interested in seeing what Wizards would do with the 5e engine outside of D&D, if only from a game design perspective.
Another poster here listed opined how all current alternate D&D settings serve to drive corebook sales. All the settings they offer always have a clause that everything in the PHB is a-ok to play. I wish I remembered who it was so I could quote it but the post is from a while back in an older thread. And I find myself in agreement with that assessment.
I really doubt that WotC would even do a setting where Core PC classes are redesigned and flat out not allowed, let alone a ground up 5e based RPG. I really think that they don't want to clutter up their D&D 'lifestyle' branding.
I think Star Frontiers and Gamma world should get a shot - but unless WotC is gonna take a real crack at what a custom 5e based game can do, and support the game line, then they are best left alone.
And to be honest, given recent 5e offerings, I'd take my chances on some well known 'amateur' game designers having their hands on the reigns over the WotC 'professionals'...