Circumstances hemmed the Pens in. It got out that Staal wouldn't consider an extension with any other team except Carolina.
At that point it was useless to talk to any other team about a trade. They would have lost big with any other team.
To get the #8 pick, a 3rd line center and another player is about the max you could expect given the circumstances.
Did they get an equal player ? Of course not. Staal will thrive down there. But they cleared cap room and if they end up with Paresi and/or Sutter the Pens are a better team than the Pens with Staal.
There obviously wasn't a better package out there or they would have taken it.