DarkMirage has written a pretty comprehensive
treatise blog post on why Kyubey’s “reversing entropy” explanation is pure bull-shitting cocks.
Kyubey can be thought of as the intergalactic equivalent of an oil field surveyor. Magical girls are precious resources, more literally than lolicons think. The battle between Puella Magi and their elder counterparts can be seen as a refinery process in which the full energy potential of crude emo is realized after being subjected to pressure and heat.
Given that Kyubey’s people have the ability to travel back in time, it should be possible for them to reverse entropy without the need for an extra-dimensional source of energy. In fact, directly addressing the problem in this manner should prove to be much more effective than using little girls like AAA batteries.
The solution employed by Kyubey and his advanced intergalactic civilization, which I estimate to be at least Type III on the Kardeshev scale, appears to be ad hoc, rudimentary and a mismatch to the level of technological sophistication they have demonstrated.
Really, the entropy explanation is extremely weak. Extremely.
Well, there’s still three weeks to go. Please don’t disappoint me, SHAFT/Urobuchi.