You aren't getting Adam Fox or Werenski for the worst of your excess though. There are some players who you just pay the cost for, those two are that type of player.
You either want elite players or you don't. Knies, despite your say so otherwise, is not an elite player. Over the last 2 years combined he's tied for 63rd in the league in goals with Lucas Raymond and JJ Peterka, and 67th in points with Slafkovsky. Right behind Morgan Geekie, Tom Wilson, Gabe Vilardi, etc. He's a lovely, lovely player. Solid 1st line winger but he's a yuuge step down from elite. Fox and Werenski are top ~5 defenders in their prime. No one should ever think of trading them, and taking advantage of another GM's absence of sense is exactly what you keep talking about. It's not about what you give up, it's about what you get.