5e Races (or Ancestries/Cultures) in OSR games...why not?

 I recently picked up this book when I found a really good deal on it:

This is kind of a rarity for me, as I don't normally pick up the nice, big, hardcover books, and...although I am probably a bit of a jerk for not patronizing my FLGS (which I haven't even had a chance to visit in my new home, FWIW)...I am REALLY enjoying reading over this.  Ravnica is probably one of my favorite fantasy settings in general and is almost certainly my favorite plane for Magic: The Gathering.  I really love how one of the most crucial aspects of the card game's identity--the five colors of mana--are an integral part of the setting, as the colors pair up to form 10 guilds that vie for control of the plane-spanning city of Ravnica.  No matter what game system a Ravnica campaign is run in, it's still going to have at least a little bit of the feel of MTG the card game (especially if there are any planeswalkers involved).

So, I'm really looking at starting up an online game set in Ravnica, but I'm not sure I want to run Fifth Edition.  I'm just not as familiar with it as I am some other systems, and if I'm already adding on the "frills" that come from gaming online, I might as well make sure the system I use is as no-frills as possible while still hitting the points I'm looking for.  Honestly, Swords & Wizardry White Box/Light/Continual Light seem just fine for such a game, and it can double up by keeping me in a Light City state of mind.

Classes seem like they'll be easy enough to handle.  Races, though...that's a different story.  Ravnica probably needs to include Loxodon (elephantfolk), Centaurs, Goblins, Merfolk, Viashino (draconic lizard-type-folk), and maybe hybrid beings from the biomantic Simic guild.  (EDIT: Oh yeah, and Vedalken!)  I'm not against creating them on my own, especially since some of that could just be reskinning stuff that's already out there.  But...and maybe I'm weird in feeling this way...there's something about reskinning races that just FEELS wrong, like it's breaking through the shared imagination of the game in a way that can't be ignored.  It's cool to say, "This is what a Ravnican goblin is like."  It seems relatively lame to just say, "Eh, play a halfling and we'll call you a goblin."  That's just...I dunno, less fantastic and more gamey.

But then I realized...why can't I just tack on 5e races to the classes of just about any OSR game and use them pretty much as-is?  I'll have to buy into some 5e-isms like Advantage/Disadvantage (which it seems gamers have accepted quite well as a mechanic fit for broad use), and I'll need an established way to resolve skills so that any skill-related benefits will have meaning...but those are minor concerns.

Movement rates should convert very simply.  Proficiencies?  If it's a weapon, that means you get to add your attack bonus when you use it.  For other stuff, it means you get to add your level to rolls.  Alignment?  There doesn't seem to be any harm in just ignoring the 5e recommendations, or in simply adopting the nine-alignment system for the game.

As examples, I think a "basic" Human build would just gain +1 to all stats and get to learn an extra language.  Or we can look at...say, the Kor from Plane Shift: Zendikar, the first of Wizards of the Coast's free PDFs bringing 5e rules to MTG:

There doesn't seem to be anything game-breaking there, and it could be fun to actually play the "official" takes on MTG's races.

Have any of you tried something like this?  Other than the "danger" of having starting characters a little more powerful than they would be otherwise, are there any big pitfalls I'm missing here?