TL;DR: Feminism is a selling point when you're popular enough, especially if it makes your entire industry more mainstream and therefore more likely to attract positive attention, fans and customers. Therefore, idol groups like AKB who have a JE-like grip on the popular market should try to cement the idol footprint and pave the way a stronger idol presence later on in the mainstream market.
Yes, this is finally where the Nishino Kana bit of this article comes in. I found it to be a very eye-opening experience to see Nishino Kana stepping up to the plate as a role-model of sorts for her legions of female, teenage fans in her latest song, 'Alright' (watch it quick, before it's taken down)
How does this apply to the idolsphere? Comparisons and discussion after the jump.