I'd probably take the trade. You have depth at RB and CJ would totally help at WR (obviously). I know it's hard to give up McCoy but CJ is the real deal. This trade makes your team a more all around good, complete team. Good luck!
QB- D. Brees, J. Freeman
RB- M. Lynch, T. Richardson, R. Hillman, D. Brown
WR- R. Wayne, M. Colston, L. Moore, J. Gordon, A. Brown
TE- A. Hernandez, K. Rudolph, B. Myers