I dont think I'd do it unless you have no other back up RBs. In a PPR league, I'd prefer Cruz over any other the other WRs involved. But it you have no quality backup RBs, I would consider it cause Sproles will be a good fill in for the bye weeks and the downgrade (imo) in WR is very minimal. Johnson and Jennings (when healthy) will be top WRs. Hope that helps.
I'd stay put as well. I love tinkering but sometimes the grass isn't always greener.
My Main League 10 Team Standard Score League: QB: Roethlisberger, Freeman RB: R Rice, L McCoy, R Mathews, A Bradshaw, D Sproles, B Brown WR: R White, V Jackson, W Welker, S Smith TE: J Graham, K: S Gostkowski DEF: Seattle (this week)
Stick with what you got. My league counts all of Sproles return efforts making him a VERY excellent RB option, but still, with such a big question mark over Jennings right now, and AJ definitely falling off this season as far as fantasy pts go, you're taking on risk at 2 positions for a small upgrade at RB over SJ.
On paper, I love the trade for you, but with injury and this season (rather than previous seasons) performances, it has too many questions for you I think.
Thanks for the help with mine, sorry so slow to reply. I don't like this deal for you either - AJ and Jennings have star power in their names, but Cruz is the best player in that deal. And you know how it is - whoever gets the best player wins the trade. Good luck!