A couple of things. I don't hate Zadorov: I hate the timing of the move. He checks a lot of boxes guys like Murph don't, but he's Zadorov, not Hedman or Pronger in his prime. He's a middle pairing guy and that in and of itself is fine, but we shouldn't be thinking he's something he's not--specifically a big-bodied
top-pair defenseman that can fix the actual defensive issues the team defense has. If he does reach that level I'll gladly eat crow, but I think he's a middle pairing guy who, like you said, is most likely an upgrade over deHaan, Maata, and Murph. I'm okay with that move in-and-of-itself.
I agree to disagree about Keith.
The other thing is the amount of roster D-men we have. Unless a move is made Keith needs a slot, Murph needs a slot, DeHaan needs a slot, Zadorov needs a slot, and Seabrook needs a slot. That's 5 guys who have waivers affixed, and make more than enough money that even if they pass waivers, they will take a chunk of the cap. The only exempt guy we got is Boqvist. Now, I've got no real issue about cycling out Boqvist (or trading him if he's not going to stick), but that's not a lot of room to see our prospects--this goes doubly so if they show that they're better than any single player of our current crop of D-men. If a lot of kids see action, it will be on a rotating basis and we got zero room in case one sticks--and that's not the best for development. Assuming Mitchell is everything his fans have hoped for--it would suck if he's gotta go down so we can see Beaudin. And, since it's not like we should be geared for winning, we can always use a guy like Seeler to fill-in if needed.
If Stan manages another D-move that gives us some breathing space, then cool. but in my opinion he should have done something with the extra middle paid guy (i.e. Murph or DeHaan) before pulling the trigger on Zaddy.