Estlor
Explorer
I think we'll see both, and I think we'll see both in the PHB(1) by the time that's ready. My expectations are that once they feel they've nailed down the Big 4 races, the Little 3 (gnome, half-elf, half-orc) will show up in the next round.
Certain aspects of the gnome will be distilled and shared by both - resistant to illusion, skilled with picks, small - and certain aspects will be unique so that you'll have a 1e/2e subrace (lives in burrows, likes gold, talks to animals) and a 3e/4e subrace (fatalist-trickster-artisan-information mongers). One will probably be +Con or +Int, the other +Cha.
Certain aspects of the gnome will be distilled and shared by both - resistant to illusion, skilled with picks, small - and certain aspects will be unique so that you'll have a 1e/2e subrace (lives in burrows, likes gold, talks to animals) and a 3e/4e subrace (fatalist-trickster-artisan-information mongers). One will probably be +Con or +Int, the other +Cha.