If he was a rightie I'd grab him and make a trade involving Ceci for some forward help. I would not trade Karlsson. You do that and you are in a full on rebuild. Chabot is not ready to be your #1 which means it's Ceci. And Dahlin will be another couple years, and there's no guarantee he will ever be as good as Karlsson or Chabot.
We have good D (once Wideman or another rightie balances the pairings and Oduya is fired into the sun). We need more Dynamic players up front.