Doughty is as good or better than Kronwall defensively.
As for Dmen to bring in, I'd be interested in Matt Greene. Big physical defensive defenseman who's not afraid to drop the gloves when necessary, right handed, Michigan guy. His contract is up this season. He's been a healthy scratch a few times under Sutter so he may have soured on that relationship a bit.
He had concussion problems in January though and I think an upper body injury, so I'm not totally sure where his health is at right now. He's also pretty slow, which will only get worse with age. But if he can be had for a decent price it could help bring some experience to the blueline.
Yeah, but I think Doughty plays better when paired with a solid defensive type, like Vlasic in the Olympics. Even Kronwall makes mistakes, but I still think he's a bit more consistent than Doughty.
I wouldn't want Matt Greene though. He's a 3rd pairing guy and would get caught up in a glut of defenseman here (Smith, Kindl, Lashoff, Almquist, etc.) He's more solid defensively than any of our kids, but doesn't have enough upside to stay in the lineup IMO.
We need a true top 4 type to join Kronwall, Ericsson, and DeKeyser. Basically we need D-man much better than Quincey to take his spot. That should be the main priority as I think all the kids will essentially fight for the bottom 2 spots.