[X] Muramasa
Of course, the really
part is that offering "wishes" they exert no control over is practically an OCP assembly line. Seriously, what did they
think was going to happen?
It was safe within the normal thresholds. The average girl only has enough power to affect a very small area, acceptable losses made up by playing conservatively for a few generations at worst. Even the most powerful ones don't hit more than a continent.
But with post turboloop Madoka, she had enough potential to rewrite the universe. Thats enough power harvested during her wish to truly FIX Entropy, properly applied.
There was some risk, but Madoka's personality profile made it safe enough to preclude a destructive wish.
The fact that he was trying to get the witch system back up and running in Rebellion springs to mind?
Also, Madoka was basically taking away the only way his race knew of how to counter entropy. Wraiths didn't exist pre Madokami, so from what Kyubey knew, Madoka was basically deconstructing the entire system his race had been building up. So I'd wager that Kyubey viewed the loss of witches as a Bad Thing.
Note you don't have Incubator continuity between universes/loops/paradoxes.
Loop 1 QB - Made a small energy profit, destroyed the MGs of Mitakihara and claimed Walpurgisnacht's grief seeds. Observed curious phenomenon of one Homura Akemi paradoxed from existence
Loop Gretchen QB - Anomalous magical girl observed. Anomalous Madoka potential observed. Collected very large cash out of energy at negligible investment, planet Earth likely ripe for harvesting colonists as breeding base for future magic research if desired
Loop Madokami QB - Ridiculously massive energy payout, Entropy solved for the foreseeable future. Megawitch self terminated by paradox. Planet Earth remains. Homura Akemi and Kaname Madoka no longer in existence.
Loop Rebellion QB - Magical girl system efficacy poor. Anomaly Homura Akemi describes efficient system suspended by artificial physical law. Test hypothesis. Oh Madokami Why.
Basically from the perspective of each timeline, they won big, and left the mess for future loop QB. Until post-Rebellion, where QB doesn't even know why, because knowledge of the underlying metaphysics was only available in the previous universe