We had a really good school overseer for a number of years, a brother who was highly placed at Bethel. I definitely learned from him. Since then, I've been appalled by just about every overseer I've seen.
I was recently counseled to work on my "pronounciation" by one. By the way, my pronunciation is extremely precise because I've been working on it since elementary school. There's plenty to criticize in my talks, but my command of English is not one of those things.
I think sometimes that the overseer just isn't paying attention and then picks random things to give counsel on. I believe I was once given a 'W' for gesturing because the overseer was looking down at his material half of the time and didn't see my frequent gestures.