I have a friend who said Ender's Game was the first novel she read in English that she enjoyed...somehow it's a book that manages to say so much, so powerfully and clearly, in relatively few words.

Yep, not a ton of Hikago AU out there. The story is just so focused on Go that it's hard to imagine the characters doing anything else. And it's such a well-written story you kind of don't feel the need to mess around with it/fix it. It's so good the way it is.