Well, it's safe to say Tony won't miss him!
I agree with others who've said that his character had come to the end of its usefulness - his arc has been played. That said, it was not easy to watch him die that way. I think all of us would have been more likely to think Paulie would have killed him, or drugs - for him to be outright murdered by Tony was a shock. However, in the grand scheme of the show, it makes sense; it's what Tony had to do. I think he's known that for a while and has been struggling with it, which played a large part in his recent downward spiral. That's what Tony meant by falling on the floor laughing hysterically after winning three times in a row at roulette and muttering to himself, "He's dead". It's the biggest load off of Tony's mind since his mother died, frankly.