Tashas solved all of my difficulties with the 5e elves.
For example, I like my "High Elves" to be dexterous and intelligent Eldritch Knights but my "Sky Elves" to be charismatic and intelligent Bards. Now with Tashas I can use the standard High Elf entry for both cultures.
I assume each culture has a wide variety of individuals, so exceptionally strong High Elves also exist.
Similarly, the Drow Elf and Wood Elf. For example, classic Drow culture is Dex first and foremost, with Intelligence and Wisdom also significant. But as a gestalt of all of the D&D versions of Drow, I prefer the Drow to be Dex and Cha, with females being Dex Paladins and males being Sorcerers. But again, even if the culture privileges individuals with these stats and gender divisions, the Drow themselves are diverse.
The decision to make the +2/+1 part of the ability score generation rather than part of the race choice, makes all of the existing Elf rules easier to use. As a DM, I can officially worldbuild specific and unique elven cultures and subcultures using normal rules. As a player, I can explore a specific Elf archetype that I want, according to the rules-as-written.
I no longer need more elf subraces. With Tashas, much of the Elf subraces that already exist in 5e can now easily consolidate to a fewer number of salient concepts, without any loss. For example, the Eladrin is more like a High Elf culture with swappable cantrip. Because a Wood Elf can now be strong, there is little need for a future Grugach Elf as a separate subrace − it is moreso a specific culture, with spears and bows instead of swords and bows, and maybe with its own specialized backgrounds.
With regard to future mechanics, I would like more swappable features, like exchanging darkvision and High Elf cantrip for a different feature, like flight or alternate beast form. But adding subraces no longer seems necessary.
