Re: Is it proper?
I had a karate instructor who was quite picky and perhaps could have provided more positive feedback in my time at his club. But he was a new instructor and a real decent guy too, I might add. Just unsuitable teaching approach/style.
One of the reasons I left was the negativity in feedback and the very low positive feedback, to me and the all the other students (including kids. which really upset me). Being one of the senior students I helped the others when they didn't understand and people were just copying each other very closely to avoid being singled out during basics, and avoided asking questions. I got to the stage where I begrudged going to training and was only going cos I felt obliged.
I left and went to another instructor eventually.
To give him his credit, he was very gracious about it and did ask for feedback while I was there. He asked for reasons for my leaving, which I provided, with suggestions for the future. I don't know if your instructor would do this if you left however...
He said he understood my leaving appreciated that it was my free time, my hobby and that I was paying good money and if I was not enjoying myself, i had every right to choose some other place train.
And he was quite right. By all means try to help him out, but it's your hobby, your free time, your money...