There are so many things that can be done.
However, what they require are fundamental changes to the collective bargaining agreement. The NHLPA has a strong union and they're not going to simply give up 8 year contracts because it makes the league better; that's not their problem. So the NHL has to give them something in return which would make it worth their while. I've suggested numerous times: Allow true free agency at the age of 24 or with 5 years of NHL accrued seasons.
Free agency when a player is in the middle of his prime? You want a way to turn things around for your franchise overnight, that's one way to do it.
It makes too much sense to just ignore. It would actually be beneficial for both the teams & the players. The players have more leverage on the team that drafted them to pay them quicker and teams have a better chance to get a player in the middle of their prime to improve the team overnight.
Plus, the fans love player movement. There's a reason TSN & Sportsnet do Trade Deadline and Free Agency shows, there are thousands of people watching.
Another way to make things better for fans, but the NHLPA would never agree to? Abolish NTC / NMC or, at the very least, make them limited where a team can only have one or two players with a NTC/NMC.
Since we're talking about it, another thing that could be done, which would be unique to the major North American sports: Allow players to be loaned from one team to another for a certain period of time. Example, this team is out of the running, we loan Brendan Gallagher for the rest of the 2024-2025 season to Tampa Bay and he returns to the team for the 2025-2026 season, unless his loan is extended. The team acquiring the player would pay his contract for the duration of the loan time. The Habs would get, I dunno, a 5th round pick.
The return would be less than a trade, but it would allow for more player movement and more teams to load up for playoff runs. It also allows teams to acquire players for a run without having to be burdened by their contract beyond the time they were loaned.
If your belief is "nothing can be done" to improve the NHL, please abstain from the discussion. I've got a shitload of ideas to make this putrid league better.