Its funny how everyone grades differently. I subscribed to Pro Football Focus today to see their premium stats, and according to them Earl Thomas has been slightly below average this year. Part of that I think has to do with playing so deep in center field and not having a chance to make plays and not being tested. But when he has had chances, he's dropped a few INTs.
There's no doubt his presence and speed enables this defense to play the way they do, and definitely should be an All Pro.
PFF has Lynch as the 3rd best RB (2nd best rusher, but below average in receiving dropped him a spot) and Sherman as the 6th best CB (3rd best in coverage).
I'm sure Football Outsiders has a completely different view on all three of these guys too.