I'm not sure why you're asking this. That long regimes can (or tend to?) get progressively worse wasn't part of my argument. I was saying that there tends to be more change at the start of a reign than later on. And therefore, absent data to the contrary, I see no reason to believe these changes trend towards relaxation after regime changes, rather than merely showing regression to the mean.

As for long-term regimes that got worse later on: Mao seems to qualify, since the worst of his tyranny (e.g. Cultural Revolution) happened later on. Hitler didn't commit any world-scale atrocities until World War II started. Stalinism was worse in the Thirties than in the Twenties, and worse again in WW2.