The teacher was obviously not a good person and his methods were abusive.

I think the point of the movie was to show that although abusive, these methods are effective in rendering results. I don't think the film made any statements on weather the means justified the end, only that the means are effective at reaching the end.

I think there was some clear respect shared between the two characters right at the end. You could see it in their faces. The teacher had finally found his legacy. You could see his feeling of justification as he controlled his student to greatness.

It was a troubling movie, but it is very true to life. Most of the best performers in arts and sports are the best because of a training regimen that is far from healthy.