In what world is Karlsson a top 3 defenseman? Might not even be top 10 at this point of his career. Giordano, Hedman, Rielly, Josi and Carlson are all indisputably better than him. There's another dozen in the conversation.
Hedman, sure. Giordano, totally fair. Reilly, Josi, and Carlson indisputably better? I for one, would dispute that. If you went Burns, Hedman, Giordano, and Jones, I'd buy that, personally. That being said, I really don't think there is an argument that Karlsson isn't top at least in the top 10, and guys like that, particularly under 30, just don't come available.
EK's contract, like the Kane, Vlasic, Jones's ones will probably look bad in a 4/5 years. That being said, over the next three the only Sharks getting raises are Labanc and Simek. Wilson has two #1 D, two top 30 centers*, and two 30-goal power forward, and Vlasic locked up. I didn't think it was possible 12 months ago, but Wilson somehow extended the window at least three more years. Losing Pavs hurts, no doubt about it, but I expect Wilson will plug that hole with a younger, faster player before the year is over.