They were all bad.
I will give my initial thoughts I had on each one before having the benefit of hindsight.
Percy Harvin.
I hated it. There was a guy in the draft that year that could do the same role that I wanted badly, his name was Cordarelle Patterson. He was on the board and Minny used Seattle's pick to take him. The 2013 Seahawks just needed a couple of pass rushers to be champs. Thank God they got them (Avril & Bennett). Otherwise I was looking at saving every dollar possible to keep as much of the team intact as possible.
In hindsight. It turned out even worse than I could imagine. He hardly played, didn't gel with teammates, and Bevell struggled to utilize him. I thought he would at least produce some results for 3-4 years, but he did next to nothing. He cost the team Golden Tate & Breno Giaccomini, which led to the Justin Britt & Paul Richardson picks. The Harvin trade was the definition of a domino effect, and classic Pete Carroll meddling. Y'see Harvin was a guy Pete coveted going back to his days at USC, and called Harvin the one that got away.
Grade: F- and quite possible the worst trade of the decade.
Jimmy Graham
When it went down I loved it. The Seahawks were the 32nd ranked red zone team in the league, and they were adding the best red zone weapon in football. Surely they would coach him up some on his blocking to make him serviceable, and they would mostly use him as a Joker TE anyway, right? Wrong. Tom Cable tried to turn him into Zach Miller and a comedy of coaching ineptitude ensued.
In hindsight the trade was even worse because the often injured Max Unger stayed healthy, and the Seahawks never found a quality Center since, outside of Britt who provided some serviceable play and 1 good year.
Grade: D+
Jamal Adams
This one is a doozy. At this point my faith in Pete Carroll and what he was doing on defense was nearly gone. The glass half-full side of me was like, "well they don't draft good players in the 1st round anyway, so he's the better option." But I knew based on this staff's history that they loved to square peg, round hole players, and Jamal Adams was just the latest victim.
The baddest part of the trade was the Jets talked the Seahawks into 2 first rounders because the Seahawks win a lot so they would be more like 2nd round picks. Seattle should've retorted with building in some top 15 protection, just in case as added insurance. Pete Carroll and the Seahawks got destroyed in this trade by a country mile. They paid a QBs ransom for a box safety. This trade is so bad that it might cost the team it's Franchise QB.
Grade: Bill O'Brien (The Lowest grade imaginable.) The worst trade of the decade and I don't even need to see the rest of the decade play out.