My plan would be very simple. 3 things:
1) Stay the course for the most part, but create some versatility with different styles of players. Don’t go all speed and skill everywhere create some grit on a few lines. The Leafs offense was stifled for 2 reasons; great goaltending and physicality. Heavy forechecking led to the injuries of both Jake Muzzin and Tyson Barrie. That forced weaker players to have to play or have to play more. Get guys who can do the same for your team.
2) UFA’s can walk unless they come back cheap like a Spezza. Any RFA’s or young players with cheaper higher potential replacements already available should be traded like Dermott, Johnsson, and possibly Kapanen.
3) Using those RFAs/young players, revamp the right side of the defense with cheap reliable defensive guys. Muzzin is currently the only Leaf defenseman I trust on the penalty kill. Find 2 more: one who is decent enough to skate with Rielly and one to skate with Muzzin which would drop Holl to 3 RD which is as high as he should ever be on an NHL roster.
Speaking with Wild fans, it sounds like a Dermott/Greenway swap could be possible, which would give the Leafs some grit on their 2nd or 3rd line while having Sandin available to replace Dermott as the 3 LD at a cheaper price.
Next I would try my damn hardest to sign Dylan Demelo. He is 27 which is close to the groups age range, is a good skating competitive defensive right handed d-man, who is coming off a $900k contract so hopefully a raise to $3 mil is enough to get him here. Not to mention he was a great complement to Chabot on the first pair and he somehow finished as a +2 on a terrible Sens team.
Then use a guy like AJ or Kappy to land another 2nd pair-ish defenseman. The misconception with the Leafs is that they need a top pairing guy and a 2nd pair guy. They don’t need that type of talent, they need guys who can handle those minutes. Your 1-2 don’t have to be on the same pair and neither do your 3-4. You can have your pairs as 1-3 and 2-4 and still be very effective. Look at St Louis last year. Pietrangelo and Parayko were their 1-2 but were on separate lines. Rielly and Muzzin are the 1-2 so find the 3-4 to play with them. (Hopefully Demelo can be the 4).
Assuming you use Kappy and picks or prospects to get the defenseman, trade Johnsson for picks and/or prospects to free cap space. Robertson is cheaper and has more potential and with the acquisition of Greenway, it would push Johnsson to the 4th line where he has no business making $3.4 mil.
Roll out the following lines:
Hyman-Matthews-Marner
Greenway-Tavares-Nylander
Robertson-Kerfoot-Mikheyev
Korshkov(?)-Engvall-Spezza
Rielly-trade/DeMelo
Muzzin-DeMelo/trade
Sandin-Holl
Anderson
Campbell
Is it perfect? No, but it maintains the Leafs potent offense while making the Leafs defense more structured and physical. All while remaining close to being cap compliant at $81.5 mil.