I'm also on the breakup M&M train...
One of the reasons IMO that both have been shut down, is that the "book" is out on them. Matthews used to create chances & goals with the puck on his stick playing alongside the likes of Hyman, Johnson, Kapanen, and Brown. Montreal has figured out how to defend it, and there's nothing they're going to do that's going to change it.
Keefe showed a tendency / inkling to throw the big 3 out there together to get a goal. I think he should do the opposite.... create an absolute nightmare matchup-wise, and run 3 lines that can each beat you...something along the lines of:
Hyman-Matthews-Mikheyev
Galchenyuk-Kerfoot-Nylander
Foligno-Spezza-Marner
Thornton-Engvall-Simmonds
Kill them with speed in the first 2 groups. Yes, they'll know the puck is still going to Matthews on that #1 line, but Mikheyev has great north-south speed to open up the game for him. The second line has been solid all series long. The 3rd line may not play with as much speed, but you've got a guy in Marner that's solid defensively and who likes to make plays from up top, a guy who can shoot in traffic in Spezza, and Foligno to crash & bang.
The Leafs have home ice, so it's not about "avoiding" the matchup -- it's about giving Montreal looks that they've never seen, and relying on your superior skill to create new chances rather than rely on the tried & true.