You get more value by trading "talented guys on their first contracts". That's how we got a 2nd and 3rd rounder in addition to a new starting wide receiver.
It was a no-brainer to trade Darby for what we were offered. Rex said it best recently: "You're playing in a defense and you got a corner without any deep ball skills, that's one reason probably Ron Darby's not there. It's hard, in that type of system you want a guy with some ball skills and Darby's a 'man-under' type of corner, he doesn't necessarily have the ball skills down the field, so I can see that move happening."
Sammy was more difficult, you can tell McDermott wasn't crazy about it but they made the decision that they weren't going to spend what it would have taken to retain Sammy beyond 2017 so why not get what you can for him?