I guess there might be Shadow of the Giant spoilers inherent in this post and any discussion that might follow.
I was just listening to the end of Ender's Game where Valentine says "let them pour over the passenger list trying to figure out who Demosthenes is." Randi will be on that list. Achilles was in a position to give support to an idea that Randi could have been Demosthenes, perhaps. Certainly Randi is the sort of person Demosthenes sounds more like. Who knows, maybe that's why Card wrote her.
The more I think about his discussion Demosthenes, the more evidence I see that Card was at one time very much a liberal. I mean, sure Demosthenes eventually becomes the name plate of a great historian, but the persona is generally regarded as repellant in Ender's Game.