Well, I liked Pruitt better than Marbury, but I agree that he lacked the killer instinct (for want of a better term). There are better options, and Hudson may be one of them. Note that I said "may." We'll just have to see how he performs for the rest of the preseason.
Hudson has little value to the Celtics as presently constituted as an undersized shooting guard. That role belongs to House. He would have considerable value as a backup point guard, because the Damiels/House combo won't work against certain matchups, and if Daniels plays the point, Pierce and Allen will play too many minutes.
So I'm looking, first, for an understanding of the offense: being where he is supposed to be and making the right choices with the ball. He's got to move the ball, not dribble around on the perimeter, and to know where his shooters are. I want to see some penetrate and dish, and maybe a little creativity. So far I haven't seen any of these things, just a guy who is scrappy on defense and looks for his own shot.