This might be kind of a tangent, but part of the big problem with depth defenders IMO is that coaches still prize shot-blocking way, WAY too much, and teach accordingly. Frankly, and this might be me skewing things a bit in my mind, but I seem to remember Nate Guenin being an okay third-pairing guy who laid down some mean hits and provided energy to the lineup when he started in Colorado, and soon devolved into a shot-blocking boat anchor on skates. Instead of charging into the corner to take care of business, he awkwardly hovered between the crease and half-wall in a lame attempt to block any shot/pass attempts, which usually failed. Part of that has to be coaching.
I'm not going to sit here and tell you that Nate Guenin sucked solely because he was coached wrong, but I think it played a role. Now I don't know if Nemeth is being coached to block shots or if that's just him M.O., I think it's the latter because I see guys like Duncan Siemens decidedly going after the puck carrier. PN is just not a guy who lays big hits or really wins a lot of puck battles so I can maybe see why he's better suited for a shot-blocking role.
Anyway, just a thought. I'm just not a fan of shot-blockers, even though it still plays a big role in hockey today. And I haven't been ever since that season way back when the Avs were on an unprecedented run back to the playoffs, only to miss by one game because (the late) Karlis Skrastins made a return to the lineup. I seriously will never, ever forgive Q for that move.