To be honest, though I doubt it would ever happen, they could [perhaps] save any kind of Christian crazy backlash by moving the heavy extra-planar hitters: Demons, Devils...I would include Angels/Devas and other various Planetouched: Assmiar, Genasi, "Shadow-people", what have you to the "Manual of the Planes" [or whatever title that type of book will be for 5e]. Not in the DMG or MM.
I am generally not a fan of the 4e style of "16 different kobolds", but "Races" in the MM, I would expect and hope to see in that there should be listings for various "run of the mill/average/typically encountered" types.
Humans: cultist, bandit, merchant, pilgrim, etc... or to go with a later edition's mode at the very least and offer: Warrior for town guards, typical soliders, maybe bandits or pirates, Adept for spellcasters and/or specialized tradesmen/artisans, and Commoners.
Halflings: "farmer/country folk", scout, sheriff
Dwarves: solider, warpriest, etc...
Elves: enchanter, swordmage, hawk/griffon rider, etc...
Gnomes: trickster, gem miner/merchant, "forest friend"
Orcs: warrior, shaman, champion/chief.
Goblinoids, Gnolls, Centaurs, et. al. "monster races" should be differentiated similarly...with typical cultural types that a party of PCs are likely to run across/interact with (I would endeavor to keep it to 3 or less). I would think "typical commoner/average warrior, shaman/tribal spellcaster, and chief/king/leader" should suffice for most monster races.
As for "Race" in the "can I make a PC with it" sense, those belong in the DMG and I, again can only make a best guess, those will be your Warforged, your Kender, Minotaurs, Thri-Kreen...probably your "5e Planetouched" (though I would not put them there) and other assorted "Setting specific" races that folks will want for "MY campaign is in X setting, I can't play 5e without my Y!!!" I am very much hoping, in this case, "less is more" as I don't want huge page count devoted to this kind of non-DMG material.