Parise was almost moved last season. Johansson, Bjugstad, Rask, Bonino, Hartman, could all potentially be gone next season. Sturm, who has been playing LW for the most part, could be moved to C to fill the hole if we moved one of the centers I listed, opening up another spot on the LW. Zuccarello is injured for who knows how long.
So what I am saying is that having an older, worse player is not a good reason to trade a younger, better player for virtually nothing. But beyond that, Staal could have been moved for a draft pick instead of Johansson, Kunin could have been moved for draft picks instead of including a player. Foligno could have been moved instead of re-signed.
This team badly needs offensive players. Our bottom six has been great, in large part due to players that were already here. Our top 6 has been brutal, and it's holding this team back. But if we're going to be bad anyway, it would be better to be bad with young, skilled players like Donato who had shown flashes of skill and offensive ability and had room to improve than with older players who are what they are, and what they are is defensive players.
Was specifically talking about roster spots, but if you want to consider all aspects, it comes down to whether or not you'd prefer Donato or a 3rd. At this point, I'd take Donato.