Its more that a player can come up for the idea of a character, make them any race they want from an rp perspective, and have them still be viable.
Except for fighters, paladins, rangers and barbarians. Humans and half-elves are now almost literally useless on all of these classes, as these classes already get the new proficiencies that they get, which is now the only reason to ever consider playing them outside of maybe an extra skill proficiency or something that is speculated to be included. I don't think "completely useless" qualifies as "viable" but maybe I'm wrong. I get it, you now get to say that humans are THE BEST magic race because they get...armor and shields? That doesn't seem very magical to me, but hey, congrats man, I'm glad these changes which invalidate humans and half-elves (and arguably shield dwarfs) for half of the classes just so happen to work out for you.
