I get it. But it is not an urgent need by any means and it is something that you can work around if need be. I think it is odd to react to this trade with "we need a 7th dman" (which was some people's reaction) rather than "what a great trade".
We just disagree on the bolded which is fine. In any event, guys on the third and fourth line are there for a reason. Lundy is, at worst, an average 4th liner given he's generally a good defender, can skate, and can PK. I won't be upset if they don't bring him back, but I think there's a role for him next year. Harkins and Leason are less valuable in my view.
And based on what I've seen of Gaucher (admittedly not much), he doesn't seem like an upgrade even if he's bigger. His AHL Gulls stats are bad.
Lundy is, AT BEST, an average 4th liner. That's his ceiling on any given night, but he's often below it. He's an ok defender and he can PK for one of the worst PK units in the league. When he has the puck, he's a turnover waiting to happen. He's hardly the Ducks' biggest problem, but it's time for an upgrade.