I was one who took exception to your critique because you picked a game in which he received a game ball for his efforts and frankly, your conclusion was, in this case, inaccurate. Sorry, but that's a fact and I'll take the coaches evaluation. I'm not trying to bust your chops as I think you're one of the more knowledgeable posters on the board, just saying perception and reality are sometimes different.
One thing in general for you and anyone else making armchair evaluations is that often what you see and think the problem is, may in fact be the exact opposite, especially when it comes to play on the line. When you see a player appear to completely whiff, more than likely there was a blown assignment or mitigating factor that impacted the play. That's one of the reasons players dislike and coaches ignore PFF ratings, they are making evaluations without knowing all the facts. Unless you're a coach, in the huddle, at the line, know the blocking assignment, the protections, pickups, routes to be run, etc. there is no way to make an accurate assessment from watching a game on tv.
There are definitely issues with the offense and it's not just the OL & QB. I wish I could go into further depth, but there are a few players who are not the problem and Barnes is one of them.