I don't normally like NFLN articles, particularly now it rivals TMZ for gossip but I thought this article by Greg Cosell was quite interesting. You may disagree. http://nflfilms.nfl.com/2012/04/02/cosell-talks-the-slot-factor/?module=HP11_content_stream
This analysis is wrong on a basic point though: CB's are not prioritized in the draft. In fact the first RB tends to get picked before the first CB. Same for S. That has not been true for the last two drafts but it was the gospel before that.