Not sure if you are pining the blame on McAvoy for the Bruins falling "flat" on the PP But if you are I think you would be incorrect.
Pasta blew chunks on the pp, when he did get his chances he wasn't finding the back of the net.
I mentioned "when he did get his chances" because he was shut down due to the lack of threats from the other forwards on the ice.
Chychrun or Lohrei are not going to make any difference if we don't change the PP structure or bring in a guy that will take the pressure of Pasta on the PP.
McAvoy is not getting paid what his is to sit on the bench on the Power Play.
Now if we want to sit McAvoy on the PK Im all for it.
Not blaming anyone - the entire structure of the PP was heavily flawed and eventually very easy to defend. You can blame Pasta if you'd like - but the issues with the PP occur 2-3 plays ahead of him missing the net because of the lack of movement in the forward group and because the Bruins do not have a shot threat from the point or bumper.
However, since you used the word blame, would you fully absolve McAvoy of his share?
Monty didn't pull Pasta or anyone else from PP1. He pulled McAvoy and replaced him with Lohrei, with nearly immediate positive results (if only he had kept him there a little longer).
The bottom line is the Bruins need OFFENSE wherever they can get it. At the very least Jakob Chychrun provides a tool the Bruins haven't had from the back-end since Krug. This doesn't necessarily mean McAvoy loses a place on the Power Play, either, though I think the notion that his paycheck guarantees him PP1 time is a bit off-putting. The stats speak for themselves. He had ONE PP goal last year.