Not going to disagree with you on depth. However, while depth is an issue at linebacker, starters are an issue along the defensive line and the secondary.
I agree that Wilson is still unproven at linebacker, and for that matter, we don't really know what we have in Jaylon, but we have reason to hope that Lee and Jaylon will be a star-caliber 1-2 punch, while strongside linebacker is much less important in this scheme.
Depthwise, we've got Hitchens, who is at least serviceable, and Nzeocha, who we don't know enough about. Wilber's also set to stick around although I don't think he adds much more than special teams ability. I wouldn't be surprised to see these six be the linebackers we carry, although I'm certainly all for upgrading the depth.