If whatever comes next just covers the floating bonuses, then we lose an aspect of the elf archetype that has been represented in the system since at least 1e AD&D.
From my perspective, since it took all of 1.5 pages of Tasha's to describe how groups can follow the archetypes or not and offer some guidance to trade-off the archetypical characteristics, I don't see why they couldn't keep the archetype and incorporate Tasha's suggestions in whatever exists going forward. That really would be a case where we both do get the elf we want.
If everything is floating, the archetype as noted by
@billd91 is less defined.
That is the opposite of what I want.
The D&D elf traditions comprise a pluralism. There are different kinds of official elf archetypes. I want 5e mechanics to empower the player to choose and build any of these official archetypes.
My concern about enforcing Dexterity is its reductionism. The D&D 5e elf tradition includes different kinds of elf archetypes. Forcing a +2 on the Dexterity score loses the aspects of the other D&D elf traditions.
Officially, the 5e Players Handbook "high elf" represents more traditions than just the 1e high elf tradition. The 5e high elf also explicitly represents the 1e "gray elf", and the 3e "sun elf". These two are parts of D&D that I care about.
In 5e mechanics, the "gray elf" needs to improve its Intelligence score by +2. The sun elf too needs the Intelligence score +2, and totally lacks a Dexterity score improvement. The 5e Players Handbook damages these two D&D traditions by explicitly identifying as these two but destroying their Intelligence archetype.
The elf, more than any other race tradition, needs floating ability scores to represent the D&D traditions. Swapping the +2 to Intelligence best represents the 1e and 3e elf traditions.
The 4e eladrin elf with its improvements to the Intelligence score and the Charisma score is an archetype tradition that remains missing from 5e elf.
When translating the gray elf and sun elf traditions into 4e mechanics, the combination of Intelligence and Charisma best expresses these two D&D elf archetypes.
Meanwhile the narrative flavor of Charisma is a prevailing elf archetype since the beginning, as innately magical, enchanters, singers, dancers, other artists, and so on. The moon elf is especially social.
When the 5e Players Handbook mentions the gray elf and the sun elf, and other elves that the 5e high elf represents, only floating ability score improvements can authentically translate all of these D&D elf traditions into 5e mechanics.
There is more than one kind of elf archetype.
If one were to argue that the 3e sun elf wasnt about Dexterity but the 5e sun elf is a high Dexterity concept, then this disconnect from the D&D tradition itself can just as easily assert any 5e mechanics for the 5e elf arbitrarily. To change the sun elf makes it just as valid to change any other elf tradition.
By contrast, to stay true to the D&D elf traditions requires the ability score improvements float.
5e mechanics need to avoid reductionist essentialism.
There are different kinds of elf archetypes. D&D 5e can support the D&D traditions by allowing the player to build the archetype that the player wants to play.
The 5e mechanics work better when nonessentialist mechanics − both in the sense of choosing between different kinds of elf essences such as choosing which elf feat one wants − as well as being able to modify these essences such as floating ability scores and proficiencies.
Supporting a diversity of elf archetypes helps avoid a racist stereotype. Also, supporting a diversity of elf archetypes stays truer to the D&D traditions about elves. Especially, the 5e high elf needs diversification because it mentions by name, gray elf, sun elf and moon elf, who are not at all like the way the 5e Players Handbook high elf is.
