Wouldn't even count those, if we are not including hindsight.
Marchment was a mediocre middle-6 AHLer here. He worked out elsewhere. It happens. Malgin still has a better shot at turning into something here than Marchment did, so I would want Dubas to continue making those trades (because next time, it could easily work out in our favour). Rittich was necessary insurance given the injury histories of Campbell and Andersen.
For me, the only 'F' Dubas has made was that Foligno trade. That is the only move that was so short-sighted and stupid that it deserved an 'F' from the beginning. I almost feel like Dubas was not the one pushing it, because it goes against pretty much everything he preaches as a GM... And I doubt he makes that kind of move again. Didn't like it from the beginning, and unsurprisingly, it didn't work out in the end.
Another move which I think deserves a low grade is signing Thornton. He was clearly not good enough to earn a spot in our lineup but we were effectively forced to play him out of respect. The only good thing was that he was vet minimum. It wouldn't be a bad move if we weren't forced to play him.
Seems like the main thing that Dubas needs to do is to stop chasing grit and intangibles. His worst moves are all rooted in doing that at the cost of effectiveness (Thornton, Foligno, maybe Ritchie but at least he had upside, etc.). You don't need to get a bunch of finesse either, but you need to be able to bring something tangible to the table on top of the intangibles/grit, and Dubas has done a great job at adding guys like Hyman, Moore, Bunting, etc. who fit that role perfectly. Maybe not the biggest or most physical, but they work hard, have the skill to contribute, and "are hard to play against".
Not all moves work out, and unless we are doing a pure binary evaluation, most of his moves have upside and make a lot of sense. Some of his bets don't work out (Vesey, Ritchie) and some do (Kampf, Kase, Bunting). Evaluate those bets (Ritchie seems to be his skating while Vesey just didn't have a lot of offensive skill) to see if there is maybe a pattern that can improve your process efficiency/effectiveness. Otherwise, there is no such thing as a "perfect" process and certainly a few failures (and we are talking about very few failures here) should not cause you to make monumental changes to your process/philosophy when you have significantly more successes.