I would like to avoid a structure like the NBA, where every article I read I see reference to some new exception or rule or whatever. That system seems so Byzantine and arcane, I don't know how the average fan can even begin to grasp how it works.
However, as complex as the NBA's system is, they have bonkers trades, buyouts, etc. all the time. The NHL should at least consider adding some additional wrinkles to their structure, like home grown player exceptions and stuff like that, to reward teams that draft and develop players well.
The problem is the 50/50 split. They can't do anything that would upset that balance.
I think they could build some additional flexibility into the system, though. Teams should be able to use unused cap space to pay off future cap penalties.
Say the cap is 100 mil and team A trades player 1 to team B with 2 mil retention. Player 1 has one additional year left on his contract. At the end of the year, team A ends up with 3 mil in unused cap space. Let them use that cap space to pay off the retention for the following year.
They can do the same thing with buyout and recapture penalties. Cap penalties due to circumvention/breaking rules would be excluded.
Teams should also be able to trade cap space/cap penalties. They essentially trade cap space already when they use a 3rd team to retain. There would need to be a limit on how much cap space a team could acquire through trade. Say, 10%, but then get rid of or severely limit LTIR. The term of cap space trades would have to be limited as well. Maybe a max of 3 years.
This would facilitate more trades. Teams that aren't spending to the cap could trade their unused cap space to teams looking to add at the deadline. It would also help teams pay off buyouts and retained transactions quicker. And none of these things would change the amount of money going to either side.