Seeler is scary in that he has not really been a real NHL defenseman and now, at 30, is suddenly playing well.... or at least playing well with Sean Walker. I mean Torts has been as surprised as anyone that he had played well.
So you move out Forbort and bring in Seeler and hope that it's not Walker that was carrying him. You gain some more physicality, and you risk the PK not being as good and Seeler's improved 5 on 5 play being the result of a nice fit with Walker and give him Shattenkirk (who hasn't been good) instead.
I dunno, maybe it works, maybe it doesn't.
But it does sure seem like you want to know what is going on with Hanifin or trying to improve the the top 6 before you consider these secondary moves.
I think the divide isn't around that the Bruins do or don't need some more physical guys, its that the fact that they have two first line forwards, two second line forwards (who of whom in DeBrusk isn't producing like one) and a lot of guys better off on the third or fourth lines is way way way more important to fix. They have question marks around Gryz (not playing well, and likely on his way out anyway), and the bottom pairing as a whole. Once you fix the bigger issues, it might change where in the lineup you can fit or want to put more physicality.
Like if the Bruins got Hanifin, for example, who is left after that move? Does it leave you in a place where you have Gryz or Lorhei on the bottom pairing? That would make it look like a physical RD is way more important than a physical RD. Seeler has a history of playing both sides because he was just there to mash faces, not to actually play hockey. Can he continue his quarter season of actually being able to play hockey playing on that right side? Or is there someone better?
TLDR; I just think you have to do the bigger moves first and then find where you can try to sprinkle in the physicality, not solve the physicality issues and have that drive where you can add talent.
