I think that adding salary cap while restrictive will be benefitial to creativity and fun. Cause you will have to actually construct competetive rosters on a budget, and develop your players, so you can get a better team come playoffs. You'll have to scout your opponents, prepare for games, cause most of them will be competetive.
And rich team will still be able to spend their dollars on staff and scounting to get advantage that way.
I also don't want nothing ridiculosly low as cap. Just one that prevents extremes. Like having 550k roster in a league 3, for example. I think that's too much.