As much as I love Kronwall he is more of a number 2 defenceman, Lidstrom was the number one guy and Kronwall isn't quite their but close.
If Lids is your bar for a number one defenseman, NO ONE IN THE NHL HAS A NUMBER ONE.
There are not 29 defensemen better than Niklas Kronwall. Hell, there aren't 15 defensemen currently playing in the NHL that are better than Kronwall. He is a number 1. He is not an elite, hall of fame defenseman. Nor are every other team's save for a few.
On the topic of PK, I would love to have him, but not for the price we would pay. He's not "the answer," though his skill set is the boobs. I also agree with others that I don't think he would be able to be coached well by Babs.