1) Few or plenty?
Do you prefer having a small bunch of races available to PCs, such as the PHB set or a cherry-picked group of favourites? Or do you think a large array available is better? Or do you even think the sky's the limit and would like to have as many as you can find for the edition you're currently playing?
As a player, I prefer to have relatively wide latitude...even though I usually will end up playing one of a small set of options (dragonborn, half-elf, human, or half-orc, occasionally genasi, warforged, or eladrin/high elf). I find it more interesting as a player when there is variety in both races and classes in the world.
As a DM, I have always favored a big tent. I find the best results always arise from players who are jazzed to play something, and in my experience, it is
quite easy to tell the difference between "oh my gosh this is so COOL" and "oh my gosh this is so
powerful."
2) Common or variable?
Do you prefer a more monolithic approach on racial mechanics i.e. all PCs of the same race X or subrace Y must use the same stats, or do you like having mechanical variants for each race and/or subrace (without narrating them as a different group)?
As a DM: Haven't really thought of it very much. Race doesn't come with stat bonuses in DW, and I would always work with a player to make sure their character reflects what story they're pursuing if we were using a system where it is more mechanically involved. What DW does have is racial moves, which usually tweak the basic rules of a class or of relevant baseline moves in the game overall. For example, I invented a new Shaman move for a player who wanted to play an owl-person in the original run of
Jewel of the Desert, and when a player wanted to play a half-orc Ranger, he felt the existing half-elf move (which lets you take
two roles during Undertake a Perilous Journey rather than just one like everyone else) was perfectly fine with him. (Said move also dovetailed with how orcs and half-orcs are more associated with the Nomad Tribes than the city-dwellers, so narratively it worked out nicely.) By working with my players I have tried to make these things meaningful to them, things that
matter, but which don't mechanically
fix them on a single path.
As a player: Doesn't really bother me much either way, so long as I know what the DM is going for. My true preference is "there is variability, but common patterns exist for populations at large." In other words, PCs and other one-offs can diverge, perhaps strongly, but this is at least a little noteworthy. A cowardly and scrawny dragonborn sticks out a little. A burly, dim eladrin catches notice. That sort of thing.
3) Native or outsiders?
Do you want playable races strictly from the fantasy setting you're adventuring in, or do you consent to PCs of a race that normally doesn't belong to it? This is a more nuanced question... you can make a distinction between the case of a race that belongs to the setting but not the world (like are you ok with PC races from the elemental or the outer planes) and the case of a race that belongs to a different setting entirely (like a Forgotten Realms race in Dark Sun) or even a different genre altogether (like a Star Wars or DCU race).
I don't normally play in heavily pre-figured settings, nor have I run them, so this is difficult to answer. However, as a general rule whether I am DM or player, I prefer to be open to possibilities. So, I guess what I'd say is, there's a presumption of nativeness (nativity?), but if I'm the DM and a player can sell me on an outsider, I'm game--and I'd like DMs to be likewise open to being sold on an outsider if it's something that appeals to me.
Bonus question (kind of a combination of questions 2 and 3): how do you feel about using different versions of a race from different settings?
Depends on what's being sought. My motto is, "Always support genuine player enthusiasm that is not abusive nor coercive." Is the player seeking an alternate setting version purely for a power boost? Ehhh...not super keen on that. Are they wanting to explore what it would be like for someone to be in a world where everything is familiar...and yet everything is alien at the same time? That sounds awesome, I'm game for that.
So yeah. My overall preference is that things are pretty open, so long as both player and DM are acting in good faith; patterns exist but
are sometimes broken; and if the player is genuinely (non-coercively, non-abusively) enthusiastic about a thing, the DM should do their utmost to support that, unless doing so is
truly well beyond the pale. I very rarely say a hard no, and my players know not to ruthlessly exploit my generosity, and that's how I prefer DMs and players to relate to one another. Both sides gracious.