Simply put, I find grading the drafts of every NFL team to be absolutely ridiculous. Whether consciously or not, they are all based on the media's pre-conceived "consensus" values of draft prospects that may or may not actually reflect what NFL team's actually felt about that player.
Virginia pass rusher Cam Johnson was Mike Mayock's 50th ranked prospect and a guy many thought would be off the board in the second round, but instead he went to the San Francisco 49ers in the seventh round. A pick that the 49ers are now getting grade boosts for because they got tremendous "value" even though every other team passed on him for over 200 picks and the more likely explanation is that the media's evaluation of Johnson was off.
Maybe Johnson had character or injury issues that will actually turn out to make this selection a value pick for the 49ers, but the reality is that it's a process that happens every year. The Panthers got Notre Dame QB Jimmy Clausen in the second round of the 2010 NFL Draft after every media draft analysts said he would be gone in the top 10 picks.
So the next day, draft graders end up giving an 'A' to the team that picked the players that people already knew and liked and a 'D' to the team that drafted unknown players like Derek Cox, Mel Kiper's 106th ranked cornerback in the 2009 Draft.
I have opinions about the draft and I'll use this space to voice them, i.e. I'm not at all a fan of drafting a punter in the third round. However, I am not a general manager in the NFL and I do not know the value the drafted players actually had. So you won't be getting draft grades from me, sorry.