You keep bringing up how many cultural issues you have with D&D. I would very much love to see Yaarel's PH. How would you solve all the issues you think D&D should fix?
By the way, there is stuff in the 5e Players Handbook that I love! The 5e spontaneous spellcasting system for the Wizard is the best ever of any edition. The mythologically accurate Celtic-esque 5e Bard as a fullcaster is fun and versatile for the concepts of other cultures as well. And the 5e Paladin is the funnest ever.
We are now towards 10 years of D&D 5e!
The main cultural issues that I had when the Players Handbook came out have already found solutions.
Xanathars came out with the "cosmic force" Cleric. This 5e formulation seems even better than earlier editions of a "philosophical" or "faith empowered" Cleric, because the concept of a cosmic force encourages Cleric character concepts that feel more plausibly a "sacred" way of life. This allows reallife players to come up with a Cleric character concept that they feel comfortable and enthusiastic about.
Tashas came out with floating ability scores. This allows the creation of character concepts that better match the players own cultural perspectives, including my own.
It is important to me, that these two rules become part of the core rules of the Players Handbook (and 5e SRD). For example, the Cleric class description merits a rewrite to be about a "cosmic force". Different settings will have different cosmic forces that define its worldviews. In Dark Sun, the cosmic forces are the four elements, and the life of planet Athas as a fifth element. In Forgotten Realms, the cosmic forces are gods, each with its own portfolio of cosmic forces. Generally, each Cleric Domain is a legitimate sacred force. Recentering the flavor of the Cleric class to be about a cosmic force makes the Players Handbook more useful to more settings, without the feeling that Forgotten Realms (or WotC corporate intellectual property) is strong-arming player choices. The results of a cosmic force as the concept is better for the game, because it makes one think more carefully about in-world within the setting. One thinks about why the force is sacred, and what a sacred community would look like that holds that force to be sacred. The focus is on the people of the community and their sacred customs and the places of their institutions. Best yet, a "sacred force" can accommodate the sensibilities of many reallife ethnicities, so there is more room within the game for many reallife players to be comfortable and enthusiastic about playing D&D.
The Players Handbook mentions races that are significant to the Norse cultural heritage, elves and dwarves. The design direction since Tashas empowers whatever abilities are important to an individual character concept. In this case, elves that are high Charisma, Intelligence, and Wisdom (and not Dexterity) are central to Norse cultural heritage, and the Bard (voice-only, without musical instrument, plus maybe a voice-only Paladin-style oath-as-cosmic-force Cleric) is excellent for a Norse elf. The Dwarves that are high Intelligence, Wisdom, and Strength are appropriate, and the Druid and Wizard are reasonable for a Norse dwarf. (The Norse dwarf is human-height, but the mechanics are Medium, and the precise height is easy to handwaive.) The floating ability scores of Tashas allows the player to decide what abilities are more appropriate − and often more importantly for sensitive situations what abilities are inappropriate. As a DM, I am taking full advantage of the official floating ability scores for worldbuilding my settings. I feel the race design works better if all races are more like the Tashas Custom Lineage, giving the player a choice of a race feat and a race trait (half of a feat). But even now, the floating abilities is plenty of flexibility.
What Xanathars and Tashas brings to the game resolves my two main issues.
The only issue remaining is a base class Psion! I was disappointed when 5e came out without a Psion in the Players Handbook. But in hindsight, perhaps that is beneficial. I can see the designers trying hard to come up with a Psion class that satisfies psionic fans. But it is the psionic fans themselves who are divided about what a Psion should look like. Hopefully, this time-consuming process of UAs and feedback will eventually result in a Psion that most psionic fans either love or can live with. Happily, psionic content has been trickling out since the 5e Monster Manual defined psionic as a specific kind of innate spellcasting, which feels accurate to me. I am calling the psionic power source a "cultural issue" in the sense that it is the theory of magic that is closest to the Norse cultural heritage and is the one that feels the most "correct" to my cultural sensibilities. In D&D terms, the Norse figures like æsir and jǫtnar are sorta like psionic archfey, but more elemental, being aspects of the sky (airy wind, watery clouds, fiery sun, etcetera) and land (earthy cliffs, watery glaciers, etcetera). For other cultures (especially under Hellenistic influence), employing "material components" and "gods" for magical rituals is a thing. But it isnt my thing. Psionic as innate spellcasting is the part of the game that feels the most "right" to me. I see the 5e designers are trying hard to make psionics work!
So, empowering players to build more ethnically and spiritually diverse Cleric concepts, and more ethnically diverse race concepts, plus the psionic source: that is pretty much it for the main issues that I have with the original Players Handbook.
Especially with the contributions of Xanathars and Tashas, I am happy with the D&D 5e tradition.