Hmm...you know...? I was reading the wiki bit on the Slapstick Effect that was put up for review a couple of posts back, and it got me thinking. Particularly this line:

The main impediment to the development of all those neat things like phasers, blasters, death-rays and the other cool Sci-Fi weapons is the property of Handwavium to tend to protect life.
The post also mentioned that the first possible signs of weakening of the Effect were around the time of Operation: Great Justice...when a LOT of people who interact with Handwavium daily were being threatened by Boskonians and the like. Since handwavium does seem to have awareness, if not actual sapience, perhaps the lessening of the Effect was in reaction to this? It noticed that even with the Effect, a lot of its users were being hurt...and it started to ease up on the Effect so that people could develop other means of protection?