Really?does no one get how abusable that solution would be you would end up with nothing but min-maxed hybrids?
I did not propose that there should be a free pick and mix from the traits of both ancestor lineages but that there be a trait(s) that are specifically siloed off that are roughly equivalent for all races.
For example a Half Elf (mostly human) from the playtest material
Racial Traits
Resourceful
Skillful
versatile
(from elf) Keen Senses
Or the opposite mostly elf
Darkvision
Elven Lineage
Fey Ancestry
Keen Senses
Trance
(From Human) Skillful
But i would prefer if they actually built it properly with a actual sharable traits silo or take @darjr idea of a racial ancestry feat for just this purpose.