What do you have in mind? Most fights in the eastern european local circuses clearly aren't UFC level.
Although you're right that if a nation might be disadvantaged by such quotas it's Russia.
But for many Central, Northern, Southern, Western European fighters, their nationality is an advantage, not a disadvantage.
The guy who gets signed because he's the best German, Austrian, Greek, Danish fighter etc typically wouldn't get signed if they were training out of the US.
MMA is incredibly underdeveloped in large parts of the world.
And as I said in my original post, history kinda proves that, just look at the endless amount of signed and after unspectacular performances released Europeans.
Chinese 'prospects' aren't looking too hot either.