I'm also in the camp that thinks you should ask to meet with the principal about DD's teacher for next year. If DD is okay with trying to advocate for herself again, I'd have her there too.
I'd make the case that she needs a teacher who can:
1) help her improve on quick, short assignments
2) give her opportunities to shine with her long, detailed assignments and
3) will appreciate and mentor someone who wants to go in depth.
If DD can get a good teacher fit next year, the stuff from this year will probably be a bump in the road. If she has another teacher who just doesn't get it, it could create long term problems at a critical time in a gifted girl's development. It may not be obvious to you why you were chosen to be her parent but it sounds like you're fighting the good fight for her. Keep on!
