Wow, this one is huge. Let's break it down by position:
QB: You take a hit
RB: You upgrade by a lot. I can see you starting Bradshaw over Addai eventually
WRs: You take a hit at WR1, but I like Wallace and given the uncertainty with Housh's role in Balt and Jax status, I think you need some help there.
So, usually I'm against giving the best players in a trade. But you are filling needs, so I would do this. My guess is, I may be in the minority though.
12 Team League. We start 2 QBs and get .5 PPR, otherwise standard scoring
QBs: Stafford, Fitzpatrick, Collins
RBs: Charles, Mendenhall, Best, Starks, Carter, Karim
WRs: D. Jackson, Marshall, S. Smith, Green,
TE: Hernandez, Cook