Sure he's an NHL player, that doesn't mean you should trade a 2nd round pick for him.
Andrew Mangipane went for a 2nd round pick,
Matthew Knies was a 2nd round pick 57th overall, baring injury that kid is going to score 20+ goals this year.
Fraser Minten was a 2nd round pick 38th overall he is 2 goals and 4 points behind Malenstyn and he's played 11 games..
PK Subban and Patrice Bergeron both 2nd round picks, one has a Norris, the other owned the Selke trophy.
And then you have Beck Malenstyn, a 4th liner that got a 2nd round pick.
You want to know why you don't trade a 2nd round pick for Beck Malenstyn?
The answer is above, every single player I mentioned is significantly better then Beck Malenstyn will EVER be.
2nd round picks are worth more because they get you more.
Beck Malenstyn is a worth a 4th, MAYBE a 3rd and Buffalo paid a 2nd because Buffalo has no clue what they are doing.
The exceptions prove the rule that most second-round draft picks don't amount to much.
I don't want to overstate this, as those picks do have significant value, but if one were to look at the second round of the 2016 draft -- where Malenstyn was selected in the fifth round -- we would find that:
- seven players never played a single NHL game, and six players have played more than 300 games;
- 14 have played less than 100 games;
- 19 have played less than 200 games;
- 25 have played less than 300 games; and,
- only 11 players are still active in the NHL this season.
On the other hand, you could point to Alex DeBrincat, Samuel Girard, Philip Hronek, Jordan Kyrou, Ryan Lindgren, and Dillon Dube -- the six players with more than 300 NHL games to date -- as products of the 2016 second round, but they are hardly representative of the full spectrum of that round of the draft.
I quite agree that second-round picks are too valuable to throw away, but I quite disagree with the selective presentation you give to the issue.
As to whether Buffalo overpaid with a second-rounder for Malenstyn is beyond me, but it's certainly open for debate and within the realm of reason.