No, the flavor can still be there... the book can still describe the typical dwarf and elf in that way.
But the mechanics no longer reflect the narrative.
The game however, doesn't need to attempt to portray this by using minor ability score bonuses. 1) Because it inspires/lightly forces players more often to make use of those bonuses and continually play classes for which those bonuses apply
This is a good thing it means the players are more likely to play classes that reflect the narrative, it rewards players that reflect the narrative, it is good design.
2) Because players can set their stats however they want... so often you WON'T have sturdy dwarves and lithe elves-- thus rendering the idea that these ability score bonuses accomplish something meaningful completely moot.
You can't have it both ways, players can set their attribute however they want (assuming standard array, assign where you like or point buy), but they are rewarded when they make use of the bonuses in the (old) mechanics, so they tend not to give the elf a 8 in Dexterity (upped to 10), and more often put a high value to exploit the bonus. Thus the ability score modifier accomplishes something meaningful by encouraging the player to reflect the narrative. Again good design.
When people say they need elves to get a +2 DEX to illustrate how "graceful" they are... they are thinking about the elven species on the whole.
Yes because on the whole PC are encouraged to they put higher values into Dexterity. So in the elves players come across in the party and NPCs tend to have higher than average dexterity.
They see +2 attributed to the race write-up and it allows them to visualize the idea that every single elf is somehow more graceful than everyone else. But that doesn't take into account that a whole bunch of other races also get a +2 DEX, meaning that elves aren't actually more graceful than anyone else, they are only equally as graceful as like a half-dozen other species in the game (including some variant Humans who put their +2 into DEX).
It doesn't matter about odd variant humans because when looking at species as a whole, you are looking at a bell curve, and while an out lying human (with +2 Dex) will be in the upper quartile for their race, a similar elf will just be average for theirs.
And it also doesn't take into account that just because they desire to see all elves as these lithe and graceful creatures... the +2 DEX only applies to Player Characters...
No it doesn't. Check out any of the elves in various NPC in monster books or other sourcebooks they virtually all have higher than average Dexterity (and were written under the old rules).
and more often than not that elf in the party WON'T be more graceful than many of the other characters.
Yet earlier you said inspires/lightly forces characters of those races to make use of those bonuses, so they will. At least they would under the old rules, unless they are specifically playing against type.
In fact, you can easily have parties where the Dwarf has a higher DEX than the Elf does.
Yes that is to be expected with bell curve distributions within a population, but the case where an Dwarf has a higher Dex than an Elf, are the edge cases and aren't anywhere near as common as the Elf having the highest Dex in the party.
Thus proving that ability score bonuses don't accomplish what they are trying to do.
Thus proving ability scored do exactly what they are trying to do, reward and encourage players for playing characters that reflect the narrative norms.
If the primary elf we see in the campaign week after week, session after session is a blundering fool compared to the dwarf, what did that +2 DEX functionally accomplish towards the description of "elves"?
But that's not what we use to see, group after group elves had the highest dexterity in the party, and played classes that exploited that racial Dexterity bonus.
Nothing. So why bother having it as a game option, when all it does is cut down on a number of other game options people will feel as though they are willing or able to play?
Cutting down the options is desirable, it helps enforce the narrative realities and reduces decisions the players need to make early on, "Oh you want to play an archer, you might want to pick elf as your race then." it's good game design. Once a player has more experience and knows the norms they can play against them with their Elf with 10 Dex and 16 Strength, and again it rewards those players because they are special acting against the norms, not just another Fighter with maximum Strength.
The game of Dungeons & Dragons wants characters to have high primary stats. And that can run counter to what the narrative of the campaign world might feel like it wants to get across. And when those two things are in disagreement...
Only the narrative and the mechanics were in agreement when they gave a racial bonus to elves' Dexterity. Now they don't agree.
I believe (and I would say at this point WotC does too) that the game takes precedence.
I would say the narrative takes precedence, and the mechanics where possible should reflect that.
Make the game more open to more players.
Having the rule either way makes no difference the openness to players.
And then let those who want to restrain their game's options do so... but do it on their own time at their own table. After all... you don't need the book to tell you that all Elves should put their +2 bonus into DEX... you can just tell your players you are instituting that rule yourself.
Except what is in the rulebooks will become the standard and what players expect.
Anyway it's a moot point, the power gamers got their way. Everyone gets a 20 in their primary stat, now everyone is "special".