I absolutely understand your frustration, but I personally don't think that I would write the letter (or maybe I'd write it for the cathartic experience, and then never send it
).
Most teachers DON'T know what to do with HG+ kiddos, from what I've seen. They are RARE and I have to keep reminding myself of this as I shepherd my DC through their school experience. I do believe, though, that MOST teachers have good intentions (and we did have one very, very bad experience - so I do know where you are coming from).
Now if the school asks for feedback, I'd feel free to give it, while keeping in mind that you DON'T want to burn bridges. Because our DC's educational needs change so quickly, you may need the school resource in some capacity in the future - and things can change at the school, too.
Since the teacher is leaving anyway, I might approach the principal with feedback about how to spot and help kiddos like your DS. I always like to throw in what the school is doing well, too, because I do think that helps you be "heard," if you know what I mean?
All the best and here's to hoping next year is better for you and your DS!
