I think the Islanders trade works out for both teams. The poster who started the thread was looking for a top 6 RW, but I think the Islanders, who are missing Grabovski, benefit by adding a #1C behind Tavares which stabilizes their roster and pushes depth players playing in their top 6 into positions in the lineup they should be playing at.
The thing is like you mentioned is Krejci's NMC. It's something that is always brought up and should be because Krejci likes it here in Boston and decides whether he leaves or goes. If he is willing to waive, I think the Bruins should look for a deal similar to the one I proposed.
I would do the proposed Arizona deal as is or like you mentioned, replace Czarnik with a B-level prospect and a 3rd/4th. If the Bruins don't trade away Krejci, then I don't see the need for trading for someone like Hanzal.
I just think the Bruins need to do something trade-wise. If we expect Krejci to be a Bruin for the long run, we can't have Backes playing on his wing:
Marchand - Bergeron - X
X - Backes - Pastrnak
X - Krejci - X
In my opinion, the top 9 above should be what the Bruins top 9 should look like. If the Bruins want to keep their core forwards, forwards in the lineup above, and don't trust Spooner at C, they should package Spooner for a RW and a defenseman. I would also like for the Bruins to waive Hayes if no other team wants him, trade Beleskey, and fill the rest of the lineup with guys like Heinen, Cehlarik, DeBrusk, Vatrano, and Czarnik. Lines 2 and 3 right now are brutal and just swapping Spooner with Schaller (3rd to 4th, 4th to 3rd) in the lineup at today's practice isn't going to change the overall play from the forwards.