It seems a LOT of people are unaware of beauty biases in Japan. There is a whole HUGE industry of skin lightening products. Simply put, Japan traditionally views paler skin as beautiful, and darker skin as ugly. It's not at all surprising that many japanese readers were upset when someone who looked like them was suddenly "bleached" because now she's blessed by Light. The message that would send to many japanese readers is quite clear, and it's reasonable for them to feel upset. Additionally, many have mentioned that the blessing in the WN was only a 10-20% lightening. While still possibly a charged concept, a slight lightening wouldn't be reflected as white in the monochrome of manga. In some ways, there may be a bit more challenge to the artist and author to protray the change in treatment, it in no way negates the plot of the WN to keep her appearance... Chocolate milk.