I remember short novel in Forgotten Realms about half-human half-goblin - son of goblin female after sexual attack of human mercenary.
And I not remember any example of opposite.
Also i remember racism of Waterdavian nobles - who hire assassins to kill half-elven members of Noble houses...
strongest Goliath must be stronger then strongest halfling, i think.
in general, i not like how important stats become.
I played in 2e fighter with 15 str, in 3e fighter with 13 str and 15 int.
but if i want to hit in 5e - my fighter must be strong...
not skilled fighter but strong fighter.
I liked approach of playtest - when items have a attunement properties and non-attunement properties. If i correctly remember - for example frost brand will deal additional damage but not will grant resistance if character isn't attuned to it.
I saw this post too late, but still.
Skipping all math - only result:
Type of proficiency
Cost, proficiency points
Specific Tools (alchemy supplies, herbalism kit etc).
I thinked about different variations of humans for only-human setting and used Culture (Nomadic, Civilized etc), Region (mountains, jungle etc), Ethnicity (illuskan from illusk, chondathan from chondath etc) + Professional Training + Background + Heroic Backstory as elements for choosing...