I think you are discounting his defensive value. Yeah, he doesn't give you the offense you want from a corner outfielder, but he's never been worse than slightly below average hitter overall and he provides tremendous value on the defense. His worst average WAR in the last 3 years has been 1.8, which isn't lighting the world on fire, but I wouldn't call it bench guy. He's also cheapish. Andrew Benintendi got a 5 year, $75 contract for slightly more offensive productivity and a worse WAR.
That said, they have depth so a trade would be fine, but I certainly would not dump him for anything.