I think Deathstroke's Arkham Origins version very much fits the mercenary role rather than the "Military Super-Villain" one he plays in the comics. Unlike his Teen Titans counterpart, he's actually fighting for money, though he does admit he enjoys his work.
As the fight against him shows, he views Batman as a worthy opponent. I also view him as one in turn.
Honestly - I think his boss battle was the best in the game: He's a challenging opponent, he fights you one-on-one, and with an arsenal that's comparable to yours.
Plus, I like his design here. Instead of lamellar chain-mail (comics) or a full-on bodysuit (cartoons) he's got a whole new set of sleek, hard-edged armor.