The thing about the Drouin trade is that it didn't work out and there was risk, but there was also merit to the thought process behind it. We needed a top 6 center with offensive potential, and Bergevin thought he could fill that role. Now obviously, he didn't. But while we gave up a top D prospect, we also got a player who was more established in the NHL and still young. If Drouin pans out as a top 6 center the way Suzuki did, then everyone's talking about this deal as a win and we potentially have a top 6 center in place for 8-10 years. The major problem with the deal was that Bergevin did nothing to stockpile the LHD cupboard that he left bare, but the move in isolation was defensible, whether we agreed with it or not.
Likewise, there was considerable risk sending away McDonagh for Gomez. But again, this move is defensible. You get a potential 1C and you give away a guy who isn't proven and who might not have played for us if we had kept him. Sometimes these types of trades work out: Balej for Kovalev, for example. Or Collberg for Vanek, even though this was a rental. And at the time, Gainey wanted to reset the team, and acquiring Gomez might have been a factor in players like Gionta and Cammalleri wanting to sign here. So perhaps he viewed this more as trading McDonagh for the ability to add all three of those players. It's not to say it was a good trade, just that there is rationale for making the move.
Of the trades listed, the one I like the least was the 1st and 2nd for Dvorak. Dvorak was a player who had "middle 6 player" written all over him, and before being traded, he was already getting big minutes in Arizona. If he wasn't excelling there, the odds that he suddenly turned his career up a notch here in his mid-20s playing behind Suzuki weren't great. So to give up more in a trade than you had just received for Kotkaniemi left a bad taste and smelled of a desperation move to try and salvage something after getting snakebit by Carolina.