I'm going with Penelope Clearwater. The competent, sober, older-Ravenclaw-prefect role could have been just about anyone (thus fulfilling the "important character who's gender I could choose" requirement), but Penelope was chosen (thus the "make her female" requirement). She hasn't done anything outstanding yet, thus the "apparent until later".
I've had strong suspicions for a while that both Penelope and Goyle will have awesome roles to play in the future.
Isn't Penelope the only older Ravenclaw we're shown in canon?
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 87. The previous thread has passed 500 comments.
There is now a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: