I agree with SD. Goligoski is really the only clever move here, and Shero wasn't even working for the Penguins when Gogo was drafted.
In McKee and Skoula, he did what he had to do. Letting Gill and Scuderi go was necessitated by his own cap management, but it wasn't necessarily a good move (especially Scuderi-wise).
Now, that's not to say that Shero isn't a good GM, and his team has been terrific for the past three seasons (again, though, a lot of that stems from some drafting that occured prior to his arrival). Skoula was a good defenceman for the Wild and if he works out, the Pens will have made a good deal in that regard.
However, if he was really looking at Skoula as a big-time sleeper, he'd probably have made a move for him much earlier. So, how much credit he can actually take if Skoula does play well remains to be seen.
EDIT: Also, DTR, I'm not sure where you're coming from comparing Scuderi and Goligoski. Gogo's an offensive defenceman who's about the same size as Karlsson. Scuderi was and is more of a defensive defenceman.