Muzzin was crap when he first came up. I couldn't fathom what the team saw in him, because he displayed none of the traits I had heard about. Since then he's really grown and turned into a solid D man.
I'm far more impressed with McNabb than I was with Muzzin, and I think he has a chance to be a more complete player. Yes, he's played in the NHL before, but he obviously wouldn't have been up in the Kings system. Keep in mind that McNabb is two years younger. This isn't discounting Muzzins play, he's been really good overall. I think that McNabb has a higher ceiling, and it's great that we may end up with two solid guys that are around DD's age. Three if Voynov works out. That's a heck of a core that could be together for a good while.