He's the most typical "I'm a warrior and I'm built to fight" trope that I've seen in so many other BioWare games.
That he's the stereotypical warrior isn't what makes him interesting. It's that he's an enormous ass. You can't even take half the stuff he says to people seriously. Is he providing background on the Salarians and Asari or is he just trying to piss people (mostly Liara) off? He lies without hesitation or remorse and seems to treat almost everyone with open disdain. He is refreshingly contemptible.
His extended cut ending is pretty lame and out-of-character though.