Umbridge
Are there any stories that take place in Harry's 5th year where somehow the teachers (especially Snape) act/speak against her? It doesn't have to be Snarry ... could be very short as well ... maybe the students overhear teachers gossip about Umbridge or show some defiance? And then they see their teachers/Snape in a different light ... or maybe students and teachers plot together .... something like that. Everyone against Umbridge xD