Humans are doing pretty good in 6we.
Any character that has metatype at C - E can be built either as any meta or as a human.
Do it.
Build some characters. See the difference human vs metahuman makes when that's the only difference.
Yes, the metahumans can end up with dicepools 1-3 dice larger. However, if they do, Humans end up with a marked advantage in Edge. If Metahumans have Human-like Edge, then they'll end up with Human-like stats across the rest of the board, too. "Human, but with Low Light vision" is not a very compelling elf or ork. And as Hobbes pointed out, while the elf or ork doesn't need to spend resources on gaining low light vision, racial qualities are a bunch rather cheap capabilities to acquire or replicate.