Just from what I've seen/heard of McKelvin, he should be a pretty solid corner for us. His hands aren't great, but he does have pretty good instincts, ball skills, and good catch up speed. There are no guarantees, but I do believe he will be an upgrade for us @ corner.
In a class w/ Nate? Why not? Now, had Clements worked his tail off (ala Jerry Rice) to refine his game instead of just relying on his ability, the answer would probably be no.