I think the biggest issue with these kinds of situations is that the payoff almost NEVER matches the buildup.
We know this whole mess will get resolved, and Washio will eventually be cleared of all accusations. But will the teacher actually get what he deserves? And will the dragon girl face even a fraction of the consequences, despite clearly being involved—even without the brainwashing at play, as shown in the last few chapters?
Nah. The teacher might get fired or something, but that's probably it. And the girl wll most likely be forgiven instantly. Then, of course, they'll all go back to being the bestest best friends evah—until the next arc rolls around.
This kind of thing has been happening a lot in manga in recent years, and I seriously hope I’m proven wrong this time.