Previews aren't called previews for nothing.
They are experiments, the means that a director, cast and crew can look at their work, iron out the kinks, the bumps. Theatres charge for previews because they have to keep the lights on, and if a house is lucky to attract a mega-star like Benedict Cumberbatch, it can make enough money to subsidize lesser productions; and pay staff.
This is solid business sense. But for a major paper like the Times, a paper that the rest of the world still considers "the paper of record" to review a production in preview, sets a bad, a dangerous precedent.
I'm speculating here, but consider this: what if the director of this Hamlet thought: "Ok, we've put the Lego Hamlet on YouTube and maybe most of the people coming still won't know what this is about. So, in the first week, let's play: put the major soliloquy at the top of the show instead of inside the play where it belongs. If it fails, we'll put it back."
No one could have imagined that a critic from a major paper would show up to see that work, let alone write it up and give it two stars!
I don't really blame the critic. What could she say? "No, I'm not going. It's too early. You can fire me if you don't like it!" She had a job to do and she did it. My condemnation rests with the newspapers who have reduced all of the arts, culture itself to such a tiny place in the scheme of things that culture is becoming just another branch of the entertainment industry.
Entertainment standards are what we judge everything by now - from politics to what apple we buy at the supermarket.
That's the way it is. But this breach of protocol matters because it can make it even harder for theatres to take chances; harder for new writers, new actors, new directors to come into the art form; to work outside of the mainstream. It makes it harder for established writers; actors; directors to try something new, do something new. Theatres that have "studios" for research become nothing more than try-out shops for the theatre's stage, instead of spaces where risk can be taken, boundaries broken.
One reason a house would book a star Hamlet like the Cumberbatch/Hamlet is because it can pay a lot of bills; feed a lot of people lower down the ladder; but not if it's killed before it even has time to breathe. Most of the people who come to see the show don't read reviews and could not care less what they say. But the art form is severely, negatively affected. And that matters. Sure, the show is sold out, it'll go to Broadway, etc. etc.
But I'm sure that Cumberbatch was appalled to see his work critiqued so early, not appalled for himself but for his fellow actors; the crew; the director; the House. It all rides on him, and the lesser actors may have to carry the burden of being in THAT production: the two star; "flat" Hamlet.
And the production won't have a do-over. The reviews may be in newsprint and online. But they're etched in stone.