Hendersons problem (at the moment) is that he's a crab. Two thirds of his passes go sideways or backward, so if you're expecting him to be a creator a la Gerrard (who he was compared to a lot a year ago) you're going to be disappointed (although I'm sure he'll develop that side of his game).
He is generally on target with his passing, and you'd think maybe his job is to get the ball and give it to a creative option like Adam or Gerrard, but getting the ball has never been his strength either.
When he first broke through at Sunderland he played a lot on the right, and I think thats where he's going to have to be played for Liverpool in the next year or two. He's not the best crosser, but he does create chances cutting infield from the right side.
FWIW, my mackem mate reckons he's been useless since his England debut. I'm putting some stats together to see exactly what has changed about him since then.