Actually, jayden, glad you brought that up. I had been thinking about this last week but I forgot it.
We currently add a non-playoff bonus so that the teams that miss out on additional games' improvements can "keep up".
What about reversing that? The teams which compete in the playoffs receive a regression instead. We just roll back their levels to pre-playoff skills.
That way we 1) simulate post-playoff fatigue/next-season hangover; and 2) keep leaguewide skill levels from improving for no reason.
I suspect the original plan was to keep any one team from being dominant for too long, but the results from seven seasons indicate that NO team has had an extended run of dominance that I've seen.