As is, there are no stats for NPC halflings in 5E. There are stats for NPCs, and then there are the adjustments provided in the PHB and/or DMG for creating halflings, which you apply to NPC stat blocks to create NPC halflings. If there are no recommended default adjustments anymore, then what would a player - one that doesn't want to make them up himself, but create something "default" according to D&D lore - use to create a typical halfling?
I point this out to people all the time, but if you actually read the Monster Manual section for thos NPC statblocks, they say that you can
customize them by adding the racial modifiers and abilities. So, by RAW, if you take a commoner statblock with all 10's, that is a default RAW halfling commoner right there. To give is a +2 Dex is to customize and homebrew it.
Now, I grant, this makes it hard for you to go and use such a statblock for a halfling PC, however, you can read the racial write up and compare to the statblocks for other NPCs. Goblins, Lizardfolk, Orcs, Elves and Dwarves all have specific statblocks that you can use to get a baseline (sure it is drow and Duergar, but they are still fairly close)
The issue we see with that though is fairly immediate for people who wish to claim universality amongst the race.
Lizardfolk are a good example, posting stats in this order str/Dex/Con/Int/Wis/Cha
Lizardfolk -> 15/10/13/7/12/7
Lizardfolk Commoner (from Saltmarsh) -> 15/10/12/7/12/7
In both cases their highest score is strength, in the case of the monster manual followed by Con. What bonuses do they get? Constitution and Wisdom. Which makes no sense in this context, even their commoners are shown as being 5 pts higher in strength than a human. Sure, Con and Wisdom are their second and third highest stats, but this is what is supposed to "define them" and they seem to be defined by strength.
But, this makes sense for the game, because Lizardfolk need to be a low level threat, so they can't be casters, and therefore they need high strength to be able to hit the player characters. Very few entries that aren't "hidden enemies" (Succubi, Yuan-Ti purebloods, ect) or spellcasters actually have a mental score that is higher than their physical scores, because they need to be threats in combat, and in combat what we care about is having a score high enough to be threatening.
This is also why a common drow has a 14 dex, not a 12, because they need the boost to still maintain a CR 1/4 threat. And once you break that CR, they jump up to an 18 dex. Because it isn't a matter of "how dexterous is a drow" it is "what value is needed to be a threat for this level."
My group has several basic human PCs. I've even played a few! Sometimes you don't have a particular vision for a character when it's game time, and you just put together the defaults and figure them out as you go.
And the point I was making is, if the halfling barbarian player wanted to create a human PC for once, he would presumably want something different from what he usually wants out of characters - something besides subverting expectations. And even if he did, he's probably going to rely on other expectations, like the quick builds for classes. So having default assumptions is always helpful to him and players like him.
Right, so if he wants to play a Dhampir he is, to just quote you "probably going to rely on other expectations, like the quick builds for classes."
So what's the issue? That he is going to have more races like humans and Dhampir's in the future? I feel for him a little bit, but this would be like me complaining that they are going to release another +2 strength +1 Con race, or another race with natural weapons that are worthless. These things already exist, I already deal with them, and while yes it is "going forward" we would need another five to seven years of releases to break even between the old way and the new way. And by then, I'm sure people will have made dozens of posts and articles about how to play these races that he can look at to figure out how he wants to subvert expectations.
Sure, it's possible we'll never see another traditional character race, and they'll all be unusual lineages designed to replace another race's traits. But a) I find it unlikely that Wizards will never add another traditional character race or subrace, especially if more campaign settings are introduced to 5E in the future and b) as such, it seems wise to make sure Wizards knows that some folks want continued support for default ASIs, so they can use new 5E material in the same way they use the old 5E material.
To B, sure, but I guarantee you they know. They knew before they released the UA.
But on A, do you really find it so unlikely? I've scoured the few source books and resources on the various settings and there aren't really any major races missing from the game.
The only ones I've really found are the Thri-Kreen, but in doing some research on them, I discovered that Thri-Kreen are part of a larger race called "The Kreen" involving about 11 different sub-categories. With that much variety a "Kreen" lineage could be easily broad enough to have floating ASIs.
Maybe Gnolls? But we've been told that gnolls are't going to be officially released, and there is already a plethora of 3rd party material if you want them, both "officially" published (Keith Baker's Exploring Eberron has gnolls) and unofficial.
So, what is really left that can't be done with a basic feature swap like they did for the Aerenal and Valenar elves?
Just because the player doesn't know what to do, doesn't mean it's cool for the DM to force a decision on them. Fortunately, if there are suggested defaults, the player doesn't have to come up with anything, and the DM doesn't have to force them. Win-win!
So... the player wants official defaults put forth to force their decision, but if the DM forces their decision it is bad, it has to be WoTC forcing their decision?
That sounds like a personal problem more than one that is actually going to come up.
1) What's wrong with a DM not wanting to put in extra effort? Running a game seems like plenty enough for most, so if they want Wizards to make their lives easier with some defaults, I think that's fair.
Sure, but the amount of effort to give static ASIs is so low... like, it is literally just about 30 seconds of work to make up the ASIs. And, if the player is that desperate to be told where to put their ASIs, then the DM putting in 30 seconds of thought to define a race as "strong" "tough" "perceptive" "charming" doesn't seem like too much to ask of them. Far less than I ask of them through just basic character building.
2) You realize "all the races will be treated like humans" has been a specific criticism of floating ASIs, right?
No, and even if it is, that isn't my point. My point is, just like you said, your friend who wants to play against type already responds to human characters differently, because they don't give static ASIs. Sooo.. they would respond to these differently, likely in the same way they responded to the humans.
If a player has never come to you demanding that you create static ASIs for humans, Changelings and Warforged... why would they do so for a Hexblood or a Reborn? What makes these guys so different except that they made it slightly more explicit that the ASIs are floating?