Well this seems kind of gaslighting-ish, so maybe I shouldn't bother responding but here goes. Whether Dahlen has panned out (he's still 21 and having a nice season in Sweden, FWIW) doesn't change the fact that his perceived value at the time was higher than a broken down Burrows.
Who's to say that if we maxed out Dahlen's value and acquired, say, Patrick Eaves at the 2017 deadline that we wouldn't have a Stanley Cup to our name?
Giving up a recent high 2nd rounder for UFA Burrows at the time was overpayment.
Burrows was quite solid for us during our cup run, logging a solid amount of minutes in a 3rd/4th line role, chipping in a couple primary assists on OT winners, and overall being reliable defensively.
I would argue that him getting hurt in the Pens series cost us the series. We had to put Chris Kelly in his place. He was so awful by comparison that he couldn't be trusted to more than 3 minutes of ice time in that game 7 2OT game. Our top players played like 4-5mins more than the Pens top players because of this, and ran out of gas at the end.
People are vastly exaggerating Dahlen's value. I even said it at the time that he was waaaaay overrated. Nobody believed me.
I'm not sure why you think the perceived value of Dahlen on this hfboards had anything to do with his actual value at the time of the trade.
Edit: Also, it's important to note the going rate of players/rentals at the time of the trade. Vancouver had traded Hansen to SJ for a recent 1st round pick (Goldobin) the same week. Hansen was worse than Burrows. I'd say the Burrows trade was one of the better trades done at that deadline.