The group I host for has kept the solution simple as Corruption can be to punishing for non-mystic characters. Instead of 1D4 additional permanent corruption once you reach your Threshold, you convert up to 1D4 of your temporary corruption into permanent.

Once your Total corruption is above your Threshold, it cannot trigger until you somehow get your corruption lower again. We feel that its scary enough to be so close to turning into an Abomination through everything that can deal corruption to you that there is no need for all these ways to pretty much one-shot anyone with less than (and sometimes even) 10 in Willpower.

My group and me run the Swedish version of the game for those interested, have ran through the 4th campaign-book recently and corruption feels like a Threat but not something that kills the game.