Like I said before, you can't just look at the numbers. This isn't baseball. Stats and box scores are way less useful in football than in most other sports. The most important players on the field (o and d lineman) rarely have any stats to show for how they contribute to success or failure. You have to watch them play and see how well they did what was expected on given plays. Watching the bears and the sacks per dropback and the time Cutler had versus our sacks per dropback and how much time Rodgers had is night and day. If you see other teams' left tackles, you can see that a lot of them would LOVE to have Newhouse. That said, I'm not trying to make it sound like Newhouse wouldn't be the first guy on our line I'd like to upgrade. He's probably the most important on (I say "probably" because the center makes the line calls and some argue that's more important, though I don't really buy it). I really REALLY hope Sherrod can come back and take that sport and Newhouse can be the backup at LT and RT. It was a long time ago and on the other side of the line, but in that game against the chiefs when he got hurt Sherrod was playing the best game that I'd seen him play. And he is a better run blocker than Newhouse, though that's not saying much.
In terms of appraising our whole line, I'd say it's an above average pass to good pass blocking line and an average run blocking line depending on the situation. We're crap at short yardage but did well running the ball against some good fronts (line the 9ers) when we were balanced. This is'n't based on sack stats, it's based on seeing how much time Rodgers has and how many drop backs he has and watching other teams who have it way, way worse. Like the bears. They'll be lucky to have their line rebuilt by the time Cutler retires.