I don't necessarily disagree with you, but I do think we need to be cautious in terms of the message we are sending to our core group of players. If we do nothing under the assumption of an early playoff exit, I can see how that would be demoralizing. We want to show Matthews et. al. that we're going for it every year and aren't going to be intimidated by the acquisitions of conference rivals.
With that said, I'd stay away from rentals unless they come cheap or improve a major area of weakness. I'd prefer trying to acquire a player with some term, or, as Boston did, a player who is ready to sign instead of testing free agency. The difficulty though is just as you say, finding cap space.
We agree entirely on the rental point, which is an argument that I also made, earlier in this thread. I'm tired of watching us "nickel and dime" away assets for non-needle movers who are out of their primes and on expiring deals. I'd rather see the team move signifcant assets when need be, to add legitimate, needle moving players that improve the roster for term.
Where I disagree with you is your point about impressing the likes of Matthews and here is why. The only reason that this team isn't better than it is right now, is because it's cash strapped because Matthews, Marner and Tavares took top dollar, where as some of their peers on contenders took small discounts, leaving more cap space available to bolster the team around them. If I'm Leafs management I tell those guys the following: "You guys wanted top dollar, at the expense of the team, you guys show up and drag this team, kicking and screaming, to a Cup." See Pittsburgh and Chicago as recent examples of teams that did that with Toews / Kane and Crosby / Gino.
Dubas can't upgrade the defense core much, because he has three, 11 million dollar forwards. He can't upgrade the goaltending much, because he paid a heavy price for those three forwards. Well, it's time for those three forwards (Willy too, if we're being honest) to drag this team through a playoff round, or two, and show that they have the "right stuff" to even be Cup contenders. Only at that point would I start breaking the bank in terms of assets, to try to put them over the top.
The reality is that even after we dump Mrazek in the off season, trade Kerfoot to free up money, move Dermott's contract at the deadline and Kessel's money comes off the cap (finally), we're still only going to have limited money (with Reilly's contract extension kicking in) to try to fix our goaltending situation (again), add an impact top 6 forward and an impact top 4 defenseman.
Dubas, clearly, paid these guys with the projection (hard to fault him) that the cap would be upwards of $90 million next year, and that he'd have the adequate cap space to fill out the roster as our guys came into their prime. Instead, the pandemic happened, escrow got maxed out, and the league has committed to multiple years of $1 million dollar cap raises for the foreseeable future, rather than the multi-million dollar raises that Dubas expected.