Sens have a few holes that need patching up.
1LW - 1C - Mark Stone
Mike Hoffman - Kyle Turris - Bobby Ryan
Ryan Dzingel - Derick Brassard - 3RW
Zack Smith - Jean Gabriel Pageau - Chris Neil/Curtis Lazar
Marc Methot - Erik Karlsson
Dion Phaneuf - Cody Ceci
3LD - Chris Wideman
Craig Anderson
Mike Condon
We're lacking a true #1 LW and a #1 C. That's 2/3 of a legitimate first line and we lack a real game breaking talent other than Karlsson. We could always upgrade on Cody Ceci and push him down to the bottom pair but we have other holes that require more attention.
My ideas:
Package Brassard+White+Pick for a legitimate 1C.
Deal Cody Ceci+ for Chris Tanev.
Acquire a solid defensive #5.
TLDR: We lack two real first line players.