This is close to what the new Theros campaign does. Every character gets to choose a supernatural gift at 1st level, which is essentially a free (or extra) feat. The book lists 10 campaign-themed gifts, but also gives the option of simply taking a feat (with the DM's permission).
I've already decided that this is my new normal, that in every game I run, every character gets to take a supernatural gift or feat at 1st level.
D&D traditionally, and in the 5th Edition, does not differentiate very well between species (genetics or inherited traits) and culture (learned traits) and the D&D "races" are a mix of the two . . . which is something that's been being discussed for quite some time now here on the boards.
Roughly . . . very roughly . . . race equates to species and subrace equates to culture . . . but both levels are a mix of learned and inherited traits.
D&D would be improved, dare I say "leveled up" (heh) if that distinction was made more clear. It's always going to be an abstraction, but this would be an improvement to the game's suspension of disbelief and will help excise some of the racist baggage of how D&D treats race.
A subrace can be biological, such as an elf with waterbreathing.
There is no meaningful difference between culture and species.
The significant difference is the design space, whether the mechanics work better as a background or a feat.
Even the background itself can be a halffeat, but it specializes to provide proficiencies and noncombat ribbons, and can involve magical ribbon if sensible for the concept.
Profoundly disagree. Some racial traits are inherited and others are learned. You can separate these out and balance them so people can mix and match ancestry and culturs, and I think that's great. But saying everything's cultural or you can be physically different from everyone else in your species in a mechanical way is an excuse to just have a giant list and pick what you want, and that's not the way I want to play. Your mileage may vary, of course.
This is close to what the new Theros campaign does. Every character gets to choose a supernatural gift at 1st level, which is essentially a free (or extra) feat. The book lists 10 campaign-themed gifts, but also gives the option of simply taking a feat (with the DM's permission).
I've already decided that this is my new normal, that in every game I run, every character gets to take a supernatural gift or feat at 1st level.
To ensure that every feat balances with every other feat, both safeguards the gaming mechanics, and the health of the D&D game, and makes customizability easier by swapping one feat for an other feat.
If the design needs more powerful mechanics, then give each character two feats at level one. Then the player can use the feat to improve one ability score by 2, and use the other feat in various ways, such as two halffeats, or improve one ability score by 1 plus one halffeat, or whatever.
Maybe my exemple wasn't particularly good... how about this instead: the Gnome feat gives +2 to Int and one additional language (or additional tool proficiency?).
The extra benefit is marginal, but adds to the flavor. If you want +2 INT, the racial feat is better than a raw ASI, but if you don't need INT you're not leaving much on the table by not taking it instead of, say, giving your Gnome Monk the Mobile Feat or just taking +2 to DEX. That would be the sort of 'slightly better' level I'd like to play in. Not sure what other sort of benefits you could work with however so it might just be a dumb idea...
Maybe my exemple wasn't particularly good... how about this instead: the Gnome feat gives +2 to Int and one additional language (or additional tool proficiency?).
The extra benefit is marginal, but adds to the flavor. If you want +2 INT, the racial feat is better than a raw ASI, but if you don't need INT you're not leaving much on the table by not taking it instead of, say, giving your Gnome Monk the Mobile Feat or just taking +2 to DEX. That would be the sort of 'slightly better' level I'd like to play in. Not sure what other sort of benefits you could work with however so it might just be a dumb idea...
I feel every feature needs to be interchangeable to avoid unintentional reallife ethnocentrism.
Again, in the Players Handbook every race trait seems interchangeable, defacto. Elven weapon proficiencies can be swapped. Learning a cantrip is cultural. Walking fast is athletic training, and cultural. (There are reallife examples of nomadic tribes that run long distances.) Ability score improvements can apply to any ability, and will continue to change according to personal experience. Languages are interchangeable. And so on.
Horns or solid eye colors are cosmetic only. It is just as easy to say that an individual Human happens to have horns "because magic" or because of a distant ancestor. The cosmetics are thematics for the character concept. To use horns as a weapon is a weapon proficiency.
I feel every feature needs to be interchangeable to avoid unintentional reallife ethnocentrism.
Again, in the Players Handbook every race trait seems interchangeable, defacto. Elven weapon proficiencies can be swapped. Learning a cantrip is cultural. Walking fast is athletic training, and cultural. (There are reallife examples of nomadic tribes that run long distances.) Ability score improvements can apply to any ability, and will continue to change according to personal experience. Languages are interchangeable. And so on.
Horns or solid eye colors are cosmetic only. It is just as easy to say that an individual Human happens to have horns "because magic" or because of a distant ancestor. The cosmetics are thematics for the character concept. To use horns as a weapon is a weapon proficiency.
Ok, this where we have to agree to disagree then. Your idea would eliminate fantasy races as a mechanical concept altogether, replacing them with what seem to me to be a series of special snowflakes theoretically part of a species/culture that they are free to have nothing to do with. This is not the game I want to play.
Wrote this up last night, but didn't get finished with it. Kind of relates to the latest string of replies. On the Culture side of things, I'd also switched over to Upbringing, so would agree on changing the general label for that aspect of these mechanics.
Racial simplification.
This is to chart out the intrinsic aspects of the available races. I'll stick to the PHB races, because the full list of races is very long.
Common Races
Dwarf
Lifespan: 350 years. Young until 50
Size: 4-5 feet tall, 150 lbs, Medium
Speed: 25 feet. Speed is not reduced by heavy armor.
Darkvision: 60 feet
Resilience: Advantage on saving throws against poison, and resistance to poison damage
Elf
Lifespan: 750 years. Young until 100
Size: 5-6 feet, slender, Medium
Speed: 30 feet
Darkvision: 60 feet
Fey Ancestry: Advantage against being charmed, can't be magically slept
Trance: Don't need to sleep. Long rest in 4 hours
Halfling
Lifespan: 150 years. Young until 20
Size: About 3 feet tall, and 40 pounds. Small
Speed: 25 feet
Darkvision: None
Brave: Advantage against fear
Lucky: Can reroll a nat 1
Human
Lifespan: Under 100 years. Young until late teens
Size: 5-6 feet, Medium
Speed: 30 feet
Darkvision: None
Uncommon Races
Dragonborn
Lifespan: 80 years. Rapid development, adult at 15
Size: Over 6 feet, 250 pounds, Medium
Speed: 30 feet
Darkvision: None
Breath Weapon: 15 foot cone or 30 foot line, depending on dragon ancestor type
Damage Resistance: Resistant to the element type of dragon ancestry
Gnome
Lifespan: 350-500 years. Adult at 40
Size: 3-4 feet, 40 pounds, Small
Speed: 25 feet
Darkvision: 60 feet
Gnome Cunning: Advantage on Int/Wis/Cha saving throws vs magic
Half-elf
Lifespan: 180 years. Young until 20
Size: 5-6 feet, Medium
Speed: 30 feet
Darkvision: 60 feet
Fey Ancestry: Advantage against being charmed, can't be magically slept
Half-orc
Lifespan: 75 years, Young until 14
Size: 5-6 feet, Medium
Speed: 30 feet
Darkvision: 60 feet
Relentless Endurance: Being reduced to 0 HP instead drops you to 1 HP, once per long rest.
Tiefling
Lifespan: Under 100 years. Young until late teens
Size: 5-6 feet, Medium
Speed: 30 feet
Darkvision: 60 feet
Hellish Resistance: Resistance to fire damage
Now, these are not entirely balanced with each other.
Lifespan doesn't matter for balance. Size matters a little. Speed matters a little. Darkvision is situational. And then there's whatever 'extras' each race comes with. There's also the issue of attributes, but I'm setting that aside because any attributes provided can be balanced against each other separately from the other features.
A common feature among the races is some sort of advantage against a type of damage or status effect (charm, fear, poison, fire, etc). Those who are lacking that: Humans. There's also Half-Orcs, where it's debatable whether Relentless Endurance is in the same category.
Aside from that, Elves have Trance, Halflings have Lucky, and Dragonborn have a Breath Weapon.
To balance things out, each race should have two features alongside the basic Lifespan/Size/Speed/Darkvision. Lack of Darkvision should mean that there's room for slightly stronger secondary features.
So the first stage reconstruction would start with what needs to be added here.