If you decide that you want to draft for a specific position and not go BPA, you can't be going off the board in the first round. You need to trade down or else you're wasting a valuable asset in the pick you currently hold.
I also think forwards are the only players you can draft for based on position if you're looking for help in the near future. Seeing defenders or goalies step into the league the year after being drafted and playing regularly at an NHL level is pretty rare. A few guys do it but they're the exception, not the rule.
You could have a big organizational need for a puck moving RD at the moment but, if you were to draft a guy that fits that description, he likely won't be a regular NHLer for 3 to 5 years and a lot can change in that time frame.
tl;dr - BPA should always be the rule. Draft for position only up front and trade down if the player that fits your positional needs isn't BPA.
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