Fisherman, you made me laugh. But one thing I've learned (with apologies to AGBell) is that when one clown closes a door, some clown always shows up to open another one.
Gaveston, by the time a critic sees a show opening on Broadway, who is served by constructive criticism? Not the show and certainly not the reader. Ideally, criticism addresses its subject in its own context, and in the context of the broader culture. The function you describe (the making of useful suggestions) necessarily comes before. There are armies of dramaturgs, directors, producers who can and should make useful suggestions throughout the development of a play. When that process is dysfunctional-and regrettably it is in a lot of cases on Broadway-the criticism you call an insult is actually the only apt way of expressing the cultural context of a show that is unworthy of the platform it has been given. If you think there is too much being insulted, perhaps you should change perspective and ask whether we are being fed too much crap. Because these shows that are being castigated in criticism this season (and it is not unique to this season) are not noble efforts that failed; they are lazy achievements that moved forward notwithstanding obvious problems that just about anyone can see. Zhivago (and it is far from alone) is a poster child for properties that had no business reaching critics in the condition it was in. But writing a review telling the creatives what they need to improve, after the horse has reached the finish line, doesn't help anyone and certainly does not interest the audience for the criticism. In fact, in my experience, the last thing a creative wants to hear when his or her show just opened is what he or she should have done.