I wouldn't worry about a few months of Tavares declining further.
He'll be fine for this year, even if they had to do something like,
Tavares-Holmberg/Minten-Jarnkrok
it wouldn't be the end of the world.
Centers: Matthews, Tavares, Domi, Kampf, Holmberg, Minten.
Knies, Matthews, marner, Nylander, perhaps even Robertson have to score, and even if Tavares declined 10% he'd be close to a 60 point player.
It's just one year ... maybe the new coach knows how to integrate prospects, as he's done that successfully in the past.
Leafs haven't had a good coach for a long time, Quinn or Burns who worked with what they had. Lidstrom wasn't ever on the Leafs so I won't include Babcock.