Yes - but only if it's inhuman. One of the things that turned me off Star Trek were the cavalcade of ridiculous humans with pointy ears or funny eye brows pretending to be aliens. I really like the Mass Effect species, and I really enjoy how different species have different appearances, all save for the Asari, who I find boring. Blue Women? Really? That's supposed to be an alien race? Save for the wacky hair, their faces look EXACTLY like humans. The Asari are the most unimaginative species in the entire ME universe, perhaps one of the most unimaginative in all of science fiction - BLUE WOMEN? Really? Okay, here's my "brilliant" idea for a new alien race: Let's make purple men! Just take the average human, colour em' purple and... I dunno, make their ears slightly pointy! WOOOO! SO IMAGINATIVE!
I suppose I'm being harsh - there are many aspects of the ME universe which are VERY imaginative. But the Asari aren't. They're boring.
If they make the Quarians just "Humans with funny skin colour, and I dunno, maybe strange hands", they would have official put fan service ahead of being imaginative.
So Sure, show Tali's face. But make her look as downright WEIRD as heck. Give her three eyes, or maybe a crab mouth or a big beak. Of course, in ME1, you could KINDA see the face structure of Quarians, so if their face ever is revealed, it'll almost certainly be a boring, unimaginative "Human-with-makeup" type face that all those actors in Star Trek had.