The Pens' general manager acquired power forward Brenden Morrow from the Dallas Stars and rugged defenseman Douglas Murray from the San Jose Sharks, proving in the process that he's the best general manager in the NHL.
Shero got the guys he wanted, and he got them before anyone else had the chance to drive up the prices on them. Had he waited until closer to April 3rd, there's a chance that Morrow and Murray would have been either snatched up by someone else or pursued by other teams thus allowing Joe Nieuwendyk and Doug Wilson to drive up their asking prices and create a bidding war for their services.
Further, with one less power forward and one less refrigerator-sized defenseman on the market demand for other players of that ilk would have increased, ultimately making everyone else more expensive. You might not like giving up Joe Morrow to get Brenden Morrow, but you would have really hated trading Morrow for Boyd Gordon.
Shero is able to manufacture these trades due in part to the organization's defensive depth. He's got so many blue-chip defensive prospects in the hopper that giving away Joe Morrow isn't as severe of a blow to his farm system as it would be to a less-stacked team.
(Oh, and that business of Joe Morrow being the Pens' #1 defensive prospect? Maybe that was the case, maybe it wasn't. It doesn't matter, because the perception that Morrow was the best in the organization means more than anything. You can't count on both hands how many "next great prospects" the Penguins have traded away only to be never heard from again. Luca Caputi? Toiling away in the AHL. Angelo Esposito? Playing in the Finnish Elite League.)
Keep in mind, also, that he acquired a third-round pick in the Morrow-for-Morrow trade, allowing him to trade his second-round pick to get Douglas Murray (and a conditional second rounder in the 2014 draft, with the condition being that the Penguins must re-sign Murray after this season). The difference in value between a second round pick and a third round pick is essentially a wash. Indeed, if the Penguins choose to let Murray walk after this season (and my money is on them doing exactly that), they will have picked up Brenden Morrow and Douglas Murray for Joe Morrow and a fifth round pick.
More than this, Shero was able to deal with potential playoff teams by giving them draft picks and unknown entities instead of roster players. It's extremely difficult to convince a team that is on the cusp of making the playoffs (and both Dallas and San Jose are) to part with current NHL roster players without giving them some of your own. But by making his deals early, Shero gives San Jose and Dallas pick to work with between now and the trade deadline, thus allowing those teams to make deals with those looking to rebuild. San Jose and Dallas were able to shed players that they wanted to move on from and in the process received draft picks they can use to make a move with a bottom-feeder that can help them win today, possibly earning them a playoff berth.
The Pens have played their hand and put the pressure on their Eastern Conference foes. It's up to the Bruins, Canadiens, Jets, and any others who want to compete to decide if they want to match the Penguins aggressive moves.