1. Radically increasing the size of a Supreme Court is often the sign that a government is growing totalitarian. It's why packing the court is so controversial even if it's as simple as increasing the court size by one. Though if Japan's Supreme Court started at 15 and stayed at 15, that's not court packing. If Trump increased the court size from 9 to 15 though, pretty much everyone would be mad.
2. I don't believe in a mandatory retirement age but I do believe in term limits. That said, Congress should get time limits before the Supreme Court. The current US system is designed so that the Executive Branch is the least stable while the Judicial Branch is the most stable with the Legislative Branch being somewhere in between. As long as Congress members still have unlimited term limits, the Supreme Court Justices should still serve for life. Once Congress has term limits, the Supreme Court can get term limits that are substantially longer, and I would be okay with it.
Anyways, the boy becoming an upstanding member of society because Misora allowed him to watch her while she was having lesbian sex is hilarious.