The player-character races in (original) D&D suggested a Tolkienesque world.
AD&D added gnomes (more generic fantasy—perhaps), half-elves (more Tolkien), and half-orcs (more Tolkien).
D&D “third edition”: Same as AD&D. By this time, however, the influence of D&D has made that set somewhat generic fantasy itself.
D&D “fourth edition”: Dragonborn, Eladrin†, and Tieflings are added. (Gnomes and half-orcs are saved for later supplements.) This game suggests a world of its own.
That’s not necessarily a bad thing. Is it better to have the core books stick with tradition and save the other races for supplments? Is it better to put races in the core books that best exemplify the mechanics of the new game? Is it better to present a default setting and choose the races for the core books accordingly?
I don’t know.
†Squint and they look like elves, so you could say they aren’t new.