it can never and should never be as simple as just that.
need must be accounted for in that decision...like if the BPA is a MLB or a QB or an RB...do we really take one over DT, CB, WR, FS, etc.?
also, what is my board looking like for that position later? can i find someone of nearly equal value later? is there a thinner grouping for this position than others?
is this position as crucial for the team as others, esp. crucial enough to warrant this early selection?
there's just too many factors to take in.
Not discounting any of that. All of these things go into how you build your draft board.
Just saying if there's a guy atop your draft board when your turn comes up, I'm not a big fan of hesitating based on the notion that "you don't take Position X in Round Y".