I just went through all of our big runs this year, and I think you're way too down on Cooper.
On Daynes game sealing run, he cut #95 DT of the Cowboys on the backside, who most certainly would have tackled Dayne. Just because it was too the left doesn't mean much.
Also, in that game, Daynes first untouched TD run was right off Coopers shoulder.
Agaisnt the Jags almost all of our big runs came off that right side, and those are the best DTs in the business he was working against there.
Dolpins game he cleared a 30-yard run for Bell.
Eagles cleared way for MA short TD run and Bell's short TD run
MA's short run against jets TD
Patriots - Sealed block for TB short TD run
TB run for 45 yards was off a Cooper block, Cooper blew somebody up badly on a screen to Bell
Lead blocker for MA 2 yard TD run
Skins helped seal of TB's first long TD run from backside, TB's run off the right side TD, out ahead knocked down the LB/S to spring him.
KC- Sealed the BVP run
Those are just some quick notes from looking at every game this year. You are being way too hard on him based on one play that cost us the KC game.
This is Denver. We do not road-grade people, we use their momentum against them and let our backs pick the holes. I just dont see how we would even think about drafting Gilles. In fact, if we do, I will buy you a dinner at anyplace you want to go. And I am broke, so that's saying a lot.

Gilles is simply too big. He does not fit the Denver mold, period.
I am not saying Cooper is all that as far as guards go, I am just saying he's not playing that badly. If anything, his Pass protection needs a lot more help than his run blocking.