Remathilis
Legend
I agree on getting rid of subraces, but I think former subraces should be developed into full races with unique traits that share a common ancestry (and therefore a "tag" that treats them as the same for certain effects). An aquatic elf should be a separate race that has its own unique mechanics, but share a "you count as an elf" tag so that they can take elven accuracy or make boots of elvenkind. If a subrace doesn't hold enough distinction to stand alone, then fold it into the mothership.Get rid of subraces. Non-humans can have cultures just like humans, but there is no reason to make it mechanical, and doing so would be problematic. An exception could be made in case of obvious and significant physical differences, but perhaps in those cases it might be easier to write those as full separate species. For example tritons are not human subspecies, so why should aquatic elves be an elven subspecies? (Not that we need both tritons and tritons but elves; one aquatic hominid species seems sufficient.)
To whit: I think the following subraces should stand alone as separate species:
Elf: high, wood, drow, aquatic, astral, eladrin, shadar-kai
dwarf: duergar
gnome: rock, forest, deep
Genasi: fire, air, earth, water
Tiefling: abyssal, infernal
And the following should be condensed
Aasimar (the difference is wing type and damage type)
Shifter (shifting type isn't big enough. Shifters should also be able to swap trait)
Dwarf: Hill and mountain are too similar
Halfling: stout and lightfoot are too similar
Goliath: the giant type is like shifting, too small to break apart
Dragonborn: likewise with dragon type.