Having two Russian stars will help them convince Gavrikov to come over (which they may have done already, but this was the cherry on top + will help him get acclimated).
Gavrikov makes Murray superfluous.
Murray + Milano + another prospect/pick or depth piece can get them a solid top-6 center (not necessarily Duchene), which would push Dubinsky down to the third line (where he'd really thrive) and could be flanked by two other bruisers who can score (PLD and Anderson)
Let's say, for argument's sake, that they move Murray + Milano + more for Duchene (in all likelihood, it'll be someone else). The lines could look like this:
Panarin - Duchene - Bjorkstrand
Foligno - Wennberg - Atkinson
Dubois - Dubinsky - Anderson
Hartnell - Sedlak - Calvert
Werenski - Jones
Johnson - Savard
Carlsson - Gavrikov
Ideally, they'd move out Hartnell's contract and put someone like Hannakainen or Schroeder on that fourth line (or, better yet, bring back Gagner at a reasonable rate) and you've got one hell of a team.