I think the knicks need a dribble perpetrating guard. He does not have to be highly efficient if he does enough other things offensively and defensively to make up for his lack of efficiency.
They need a 2 guard that can shoot 3s and play good defense. I also think they need some back bigs that rebound,score, and plays d. A starting quality center would help the cause too.
I would like to keep Calderon but I would trade him at the right price. I think he has value to a competing team that needs shooting, passing, and a veteran presence that can play on the ball or off.
dribble drivers - Dragic, Jackson, Lin(highly unlikely but his price will probably be back up level),
3pt/D guards or wings- Jimmy Butler(Extremely unlikely unless Chicago is dumb), Wes Matthews jr, Danny Green, Gerald Green
Back up bigs - Brandan Wright, Ed Davis, Brandon Bass,
Cs- R. Lopez, Omer Asik, Enes Kanter