I am sure that is some of it. For example, I have books I loved as a kid to young adult, but now I am middle aged (getting closer to grumpy old man LOL), a lot of those books don't appeal to me anymore. I have found memories of them, but when I've tried reading them over the last 10 years or so, I just can't get into them or enjoy them as much.
The other part (I'm certain) is there is WAY TOO MUCH magic in 5E's classes, races, and subclasses. NO fighter or rogue should have magic IMO. If you want magic, multiclass a bit once in a while.
Let's look at Arcane Trickster, for example. Rogues have a LOT of class features. Enough IMO that subclasses aren't even needed really. But, with AT, you get all those class features and the spell casting of a 7th level caster (even if a bit restricted). By comparison, would a Rogue/Wizard 13/7 be as good as a Rogue (AT) 20? It would be an interesting comparison....
Magic is also too easy. There is little (if any) chance of a spell being interrupted by an attack, making concentration checks happens more often than not, spell components have largely gone by the wayside due to spell casting foci and component pouches. Being also to cast spells "at-will" from prepared list instead of preassigning to specific slots makes magic even more versatile.
Supposedly these sorts of changes were "asked for" by players, but that was never my experience so I have no clue where WotC got that impression from...
I understand this completely. But I like my game to be 80% realistic so it is well-grounded enough that I can truly imagine it. The other 20% is the fantastic. Think of the movie Dragonheart (if you're a fan). If you take the dragon out, the rest is all "realistic", but throw the dragon in and it becomes "fantastic".
And if that's the level of fantasy you're comfortable with, that's perfectly fine. But D&D has always been magical to me. Evil wizards, undead, dragons, monsters who can instantly rust metal, disintegrate things with eye lasers, conjure profound darkness, or instantly heal sword wounds are common things encountered.
Weird crypts carved from the earth, with strange magical defenses and ancient treasures from a long lost golden age abound. Calling upon your gods, or unlocking the cheat codes of reality by studying ancient tomes can perform miracles, and magic exists that can bolster and enhance one's skills in and out of combat.
I mean, from the very beginning, we knew that there was something special about D&D heroes- there's absolutely nothing realistic about a 10th level Fighter wading through hordes of goblins, fighting skyscraper-sized monsters, and being punted off high cliffs and not only surviving, but
winning!
If that's not indicative of a kind of magic, I'm not sure what is, even if the Fighter's sword isn't glowing with eldritch fire, and he's not chanting words of power in battle.
When I was young, I had the wonderful opportunity to devour a bookshelf full of pulp fiction novels. Conan, John Carter, and Doc Savage were early heroes, and each of them has extraordinary qualities, and encounters things beyond mortal understanding.
Even works of low fantasy, like Thieves' World, had wizards aplenty, and an immortal swordsman doomed to heal from any wound, alongside it's jumped up street thieves, underworld businessmen disguised as innkeepers, and humble seeming storytellers who see more than one might suppose.
D&D has long kept the trappings of a medieval world, despite it's technology level constantly rising to the edge of the Renaissance, with castles and galleons, and other things that don't make sense in a magical world- because these things are familiar and expected.
But yes, the world is too magical for these things to make sense- it's a paradox. The realization of that fact is jarring, and can destroy immersion to a logical mind- you can't help but think,
if magic can do X, then why is Y? If the King of Cormyr is a 20th level Fighter, then why is he asking my 5th level Paladin to save his kingdom?
To resolve this paradox, I feel D&D worlds need to reflect these truths. Keith Baker showed us one way that D&D's magic would create a world, but a lot of people found it too fantastic, too unlike the D&D worlds they prefer.
But the existence of magic makes those worlds impossible, really. You have to use deus ex machina like "the gods say so" or "people distrust wizards" or even "these are my houserules that limit PC's to using no higher than 5th level spells".
The paradox- to make a world feel more like "classic" Dungeons and Dragons, one must change what Dungeons and Dragons
is.
Because D&D has, for a very long time now, had crashed alien spacecraft, all powerful artifacts, and magic that lets a wooden galleon sail among the stars.