Outside observer (Bolts fan) coming in peace. I am super biased in my take based on what I've seen Brisebois do and I understand that what worked once or twice in the past may not work again, but here is my $0.02 (that's probably worth even less).
1. If you're going after a rental and giving up assets, don't cheap out. You're just going to have to make the same trade next year (see: Edmundson, Schenn, Sandin for Gustafsson and a 1st, Dewar, Engvall, Lafferty, Acciari, all trades that basically got you the same guy four times over that cost assets every time)
2. Take a big swing at the player you want most if they're available, especially if they're still 20 something years old and under team control. It will require risk, and management needs to be a bit less risk-averse.
3. Unskilled depth adds alone won't get it done, even if they are technically upgrades. Whoever described the Leafs' approach as "death by a thousand roster moves" had it right. The Leafs need to figure out who their guy is, throw a draft class at the other team, and see what happens. At least if they come up short it will provide more clarity to management than basically putting the same team in the playoffs every year and not knowing what to do.
4. Stop spending assets at the deadline for diamonds in the rough/lottery picks. That's what the draft is for. It's way easier to go to the jeweler and buy the diamond, and just accept that it costs a lot to get one.
I think you guys have a really good team but it seems like management just copies and pastes the same deadline every year. The Core Four aren't getting any younger, and with Marner's future looking a bit uncertain, it's past time to take a big swing.