This is the type of coaching decision that pisses me off, and it's going to make me sound like a Blackwell fanboy.
You're going to take a guy who's been pretty positive across the board and scratch him in favor of three guys who have done next to nothing.
With his speed and pretty good vision/IQ, I see no reason Blackwell couldn't PK and potentially be good at it. He has also played center, so I don't see a logical reason that he comes out. He'd be more versatile than any of Howden, Gauthier, or Rooney.