Positional value is really, really important in the draft. You are probably 10x as likely to get a serviceable RB in the 6th or 7th round as you are to get a serviceable EDGE in the 6th or 7th round. You are also way more likely to get a good/great EDGE, OT, CB, QB in the first two rounds than anywhere else in the draft. Most good drafting teams pick guys who are liked by the consensus (more data points is better, that is pretty much the basic of predictive analytics afaik), but they also take premium positions in the first round most of the time.