Well if he comes out of the box then ya just throw your flag up. The rules state that the coach must be visible and if he calls a timeout and I can't hear him tough!
Also you say when the coach calls a timeout you'll have to turn away, its not like anything is happening because if the ball is live then just ignore any request, otherwsie flip around real quick. I would have preferred to keep it the way it was but not a big issue there.