A first and third is a high price to pay for a guy who has flashes of talent but hasn't really proven anything. Especially when we have a quality HB already on the payroll, regardless if you like the "person" or not. In addition, we'd be sacrificing all this for the side of the ball that didn't finish in the bottom 5 in rushing yards/per game allowed and just lost a shutdown corner and defensive leader.
In my mind, signing an RFA for that kind of compensation should be reserved for when you are getting as close as reasonably possible to a sure thing. A full-time starter who has proven performance and durability.
That said, if we can work an equitable trade for Turner then I'm game.