It has been leaked that the forthcoming Volo's Guide to Monsters will have rules for playing Aasimar, Bugbears, Firbolgs, Goblins,Goliaths, hobgoblins, Kenku, Kobolds, Lizardfolk, Orcs, Tabaxi and Tritons.
Setting aside my current movement towards even finding elves a bit problematic as a playable race, I can see the case for things like Aasimar, Kenky and Goliaths.
But bugbears? Goblins? Hobgoblins? I've even seen complaints that gnolls weren't included. What? These are monsters.
I guess it comes out of an assumption that I've grown to wholesale reject - A naturalistic approach to critters. Ie, that gnolls or bugbears are just another intelligent species like any other, albeit one more violent then most. In other words, they are not really monsters.
This approach, populised I suppose by the WoW/Eberron approach to orcs as Noble Savages, to me roundly defeats much of the Raison d'Etre for D&D adventuring - Namely that it is ok to kill these critters and take their stuff.
Gnolls are not just intelligent jackals. They are a horrible demonic hybrid of man and jackal whose existence is an explicit and intentional threat to human society.
Hobgoblins are not just a species of a race called goblins. They are (imc), Devilmen - Tribes of former humans who turned to devil worship and were inevitably corrupted by their association with evil. They are a diabolical mirror of mankind that represents not only mankind's potential extinction but it's ultimately wilful worst transformation.
Goblins, bugbears and ogres I treat as variations of troll (in the nordic sense of the word - Paul Anderson's take on trolls are just a genetic warmachine of a former empire) - They are something mythic, with fey associations, existing in liminal zones between the mythic unknown and the known world.
The point being - None of them are natural. They are not naturalistic species in the sense of being just another biological species with different outlook and appearance. They are monstrous. Their very nature marks them as something antithetic to mankind - They are products of cosmic forces that would gladly see mankind wiped out - forces fundamentally alien to mankind.
When human adventurers go into the wilds and meet these critters it is not just a question of fighting them because they are in the way and might be dangerous. It is about encountering forces that represent an existential threat to the very world order that mankind is part of. Of course it is justified to kill them and take their stuff!
I should note, I did take a different tack with Orcs, who to me are a bloodthirsty and more ferocious image of what neanderthals might have been had they not gone extinct, but nevertheless lost the evolutionary race with homo sapiens by the time the middle ages come around.
They are also called "Sub-men" (with all the Talislantan implications of the word) and basically a savage antediluvian cousin to men, whose long history of bloodthirsty animalistic savagery has degenerated them even further. Basically, their shot at growing as a race came and went, and they remain now only as a cancerous evolutionary dead end. Still, from this we get half-orcs as a possible player race.
Kobolds I treat as basically nasty-minded sentient rats that live on the fringes of civilization - which is more or less in keeping with the historical depiction of kobolds. I suppose if you really wanted to play as reviled chattel, you could play a kobold.