The NBA equivalent would be trading DeMarcus Cousins for draft picks, and then selecting Jordan Mickey with a lottery pick.
I think you are being too tough on the Bruins. Trading Hamilton is more like trading Victor Oladipo or Ben McLemore. Hamilton has not done anything to put himself into the Cousins comparable territory. As far as who they picked, I know nothing about them. If you are right and they all turn out to be Jordan Mickey, that will be sad but I have my doubts that it is that dire.
The experts who grade these things gave the Bruins an "F" for the draft pick they acquired in the Hamilton grade. That's about the equivalent of taking Jordan Mickey in the lottery, or maybe even worse.
Is Hamilton the equivalent of DeMarcus Cousins? No, because one player in hockey doesn't have the impact a basketball player does. However, He's a 22 year old #1 defenseman with a superstar skill set. He's been projected as a potential future Norris Trophy winner. Even though he won't reach his full potential for two or three more seasons, he's already producing like a #1 defender in all three zones.
The trade is unjustifiable, and wasting the draft pick on a guy with a mid-second round grade makes it even worse.
As far as the draft picks, I don't know as I said but even if one of them turns out to be a bust, they have 3 picks in the top 52. Hockey has 7 rounds, basketball 2 (ratio 3.5). That means #15, #45, and #52 are the hockey equivalent of #4, #12, and #15 in basketball. I still say what the Bruins did is the hockey equivalent of trading Victor Oladipo (with a worse contract situation) for #4, #12, and #15.
Now if the Bruins screw up the picks, that is a different issue altogether. Of those 3 picks, I predict one will surprise, one will bust, and one will be about what you expect. Now the Flames may lose Hamilton in FA, they may have a star for several years, or Hamilton may level off and never fulfill his promise.