The idea would be to stop raising the cap now but add the near future increases into the 20% pool. Once its harmonized you start transitioning into the new system. Or perhaps the owners approve 10% to the cap 1st year to start and ad the following years.
You could also make it floating or allow other teams to buy unused bonus cap to struggling franchises.
Its a very rough framework that I am spitting out.
Ie. We buy NYI bonus cap 1:1. They get 20million in the bank and we can now spend 20 million extra but perhaps you can only buy a max of 20million
And no the bonus could be used exclussively for secondary players if a team chooses. You could also make it so players past a certain cap hit are not eligible.
Instead of shooting it dow explore and grow ideas.
Actually if you cut the bonus system off from players making 10%+ total cap and the player is very confident and works a deal out. A lot of good players will start signing for 9.9% of cap in the hopes of playing well and leaping another player making 12% via the bonus.
Buying someone's Cap Space, has already been done by teams dumping bad players / LTIR's to other franchises, but the currency is usually picks/other assets.
Buying for cash, goes back to the old days where players were purchased for cash.
Rich teams could take advantage, but poor teams could benefit during rebuilding years. This seems like a win win, so we must fear and reject it.
Have a better bonus system than exists today.
But it should be measurable, and based on results, not projections, and limit it to X# per year.
Example:
Matthews 69 goals would be bonus worthy as a one-time payment.
Nylander career year and 2nd. leading scorer, top 10 NHL, could land him a one-time payment.
Have neither impact the Cap.
Have it come out of the non-HRR.
If the franchise can't afford the bonus costs, then they should run their franchise better.