I think they need to find that extra forward who can help them counter against the easier matchups they'll face, but not be a liability if that line gets out against tough competition. I really liked how Burrows played with Horvat during some of the limited time they've had together and wouldn't mind that at all...
...Or this, where if Kassian is willing to play ball, then he could match very well. One thing with Kassian is he seems to change how he plays sometimes based on what linemates he has. If he gets put with the Sedins, he tries to cycle with them along the boards and play a 'pretty' game. Put him with plugs and he reverts to the baser instincts of violence.
I think he'd match well with Kenins and Horvat where they'd be hard on the forecheck and using their speed to breakout and drive to the net. Have them out there for high intensity 20-30 second shifts and that would be a lot to handle for any line