Question was asked about Kam or ET on NFLN and I had to agree with the answer. The overall excellent game that Kam offers for the defense is more valuable than more center field oriented abilities that ET offers. One is more replaceable than the other, I think.
By that same token, I think that Mebane is worth 3-4 mil a season even if just for 1st and 2nd down. I'm not so sure he isn't the most dominant 1 tech/NT there is right now. As good as everyone thinks McDonald is just because he's become a bit better nickel pass rusher, he's not even close to Mebane in taking double teams and getting backfield penetration against the run. Not even REMOTELY close. He's not just a fat arse and gets into the backfield with regularity. When Mebane is out we get gashed more. And right behind him often taking the other A gap or B gap, flowing to the ball is Wagner who also really has no weaknesses and never leaves the field, unlike all of our other backers that are also highly talented that do leave the field in certain situations.
Tough call, but in my experience, playing in the middle of the field is much tougher than playing on the outside where the sideline is your greatest ally.