Nighthawk more specialist/tank then assassin
Whichever Nighthawk I see is dealing one of the least DPS, however, has the highest amount of knockdown/cc in the game. I played it myself and despite whatever you do, you do not deal a very good DPS. But you make all the elites/bosses busy and your mob of ravens take enemy's attention from other players.
Therefore, I believe this class is not really an assassin but more of a tank or a specialist.