Just my thoughts.
Draft grades in general are silly, but if you're going to do them then they have to be given relative to draft capital.
Typically draft grades are just handed out based on teams taking or not taking the players that the media already liked. So in a sense, it's just an affirmation of the consensus board. Arnold fell 12-16 slots below expectation, but that doesn't prompt anyone in the media to say "maybe we missed something here." They just say "Detroit got a top 10 player at 24." What makes him a "top 10 player?" Simply media expectation. It's circular reasoning and it excludes the critical new data we received last night: the league collectively let Arnold fall to #24.
There are reports that the Lions also called the Packers about moving up for Arnold in case it didn't work with Dallas. GB wanted to stick and pick rather than risk losing Morgan. They expected Baltimore to take him if they had the chance or maybe move up to do so. At least that's what's indicated by the rumor. That would meant GB was never taking Arnold.
Morgan certainly didn't start climbing draft boards lately. He was just higher for a team like the Packers than he was in the media. Maybe he was higher for other teams as well. We can't really know for certain.
No one won or lost anything.