The new Sith Warrior class has been revealed by Bioware and Gamespot in this new Q&A:
GameSpot: Our next profession to discuss is the Sith Warrior, which we believe was shown at this year's E3. Give us an overview of this class.
James Ohlen: At E3, we did show off a Sith, and today, we are revealing that the Sith that was shown at E3 was specifically the Sith Warrior. Darth Vader was the primary inspiration for the this character class. The Sith Warrior is a heavily armored Force user driven by darkness and rage. He depends more on overpowering his opponents with martial skills than Force powers but often uses iconic powers, such as [the] Force choke. His story revolves around hunting down and crushing the enemies of the Empire, though sometimes, he is given the task of corrupting--rather than destroying--an enemy.