I know that Duke Johnson is one of the most talented RBs in football and, if he got the ball more, could demonstrate that on a weekly basis.
But...
I find it humorous that people are up in arms about, at best, a 50/50 slot receiver and runningback, especially on a team with Chubb, Hunt, Jarvis, and to a lesser extent, Higgins and Hilliard.
Losing Duke definitely would have a negative impact, but, if he really wants out and could get us OLine help or a nice future draft pick then I would move him pretty quickly.