Re Wright - Absolutely, that was a steal at the time. I think the biggest issues were that Wright got hurt very shortly after arriving and I even heard "oh, is he finally playing?" when he DID get into the lineup. Then, the guy who was supposed to be our "McTavish" didn't do much in the playoffs and the criticism adds up. Heck, within hours of the series being done, I saw articles questioning whether he was a PRO bust or not. It was just a weird situation. That said, you pull that deal every time because 9 times out of 10, Windsor is still playing hockey right now.
Re Dionicio - I think the issue here was that he was supposed to be the tough D, but turned into the offensive/tough D AND F. Which doesn't help the D as much. I love his game, though, and I hope he's here for at least another season.
Re Castle - This was a case of a talented forward being put in a defensive role. Once he got into the top six, you could see his talent coming through. I think, with the right linemates, he'll be just fine.
You're right, though, in that the series was a perfect storm. The Rangers were as "on" as we've seen any team all season and the Spitfires simply couldn't find an answer. Whether that was fatigue (which would be justified), issues with the lines, or simply beaten by a better team at the time... or even some combination of the three... it happens. It sucks, but it happens. No single person was responsible for everything, whether that be Wright, Savard, Maggio, Bowler, or some random player. This is why I gave props to the Rangers. They did their part to perfection.