Kevin Stevens deserves credit for Marino... Pete for Sprong was a fair trade... Zucker was good... I’d mention the trade that is now just McCann. That was a decent trade... The whole Kessel thing is too complicated to pin on just him...
However, you can cite as many bad trades/signings as well.
To be fair, some of the "bad" trades are trades viewed based on results rather than "at the time" value. Like Sheahan and Brassard.
Sheahan+5th for Wilson+3rd. Wilson was a fringe player and Sheahan filled the 3C nice adequately but it never clicked. Performed as expected.
Brassard for Cole, Gusty, 1st (think Reaves too). Brassard was the premium center available and this was widely applauded. We were in a position to three-peat better than any team in the cap era.
Both turned out poopy due to their play and overall impact but that doesn't mean they weren't good trades. Then he takes two non-impact UFAs to be, a 2nd, and a 4th and turns them into Bjustad and McCann. That's another pretty good deal that took advantage of Florida's desire to cut salary. Again though, Bjugstad didn't perform here and alas had to be traded. McCann is a young, versatile center/wing for us. Each trade at the time made the Penguins a better team, at least on paper and in theory. Those players brought in that didn't perform as expected often bias the trade itself towards the bad side.
In reality, I can only think of the one bad signing in JJ. All others have been fair. I thought Phil was traded for less than what he was worth but JR didn't have much leverage and Kessel vetoed and much better swap with Minny. Not totally JR's fault there. With the Zucker and Kapanen trade now though, the price he paid was slightly higher than what most of us would have liked. Basically a 1st and a dump for Zucker (I tend not to include Addison because we got POJ in the Kessel trade) and then a 1st and a quality prospect of Kapanen. Hefty prices but he brought in two help now players that fit our style. Last, he swaps Horny for Matheson which we can debate all day and all parties are right. Jarry got signed to a fair deal as well. So really...it's the JJ signing that's been a bust.
Being at the end of the window with the mandate to still win now, I'd rather have the horse trader in JR than a GM that sits on his hands and doesn't make moves hoping that one draft pick helps us in 4 years.