indytallguy, I agree with you that a critic's constructive criticism is always helpful to future runs of the same show. However, I also think that they can be helpful for Broadway -- rather than close a show, there's nothing stopping the producer and director from revamping the production, or at least tweaking it.
I noticed that several critics complained that Dr. Z. seemed to channel Les Miz, rather than providing something new. This may well be part of the problem, although I don't know because I haven't seen it. Another difficulty may be that it's hard to root for either side -- Zhivago may be a poet, but he's still a wealthy Czarist who is cheating on a very sweet wife (at least in the movie). As for Strelnikov, why would we root for a violent Communist revolutionary?
I hope that we see a lot more of Tam Mutu, despite the show's closure. He has a heckuva voice, and he's certainly pleasant to look at. If Rebecca ever opens on Broadway, he'd probably be a good male lead for that show. For that matter, if Love Never Dies opens, he could always play the Phantom; he was the backup Phantom to Ramin Karimloo in the London production of LND.
Audrey, the Phantom Phanatic, who nonetheless would rather be Jean Valjean, who knew how to make lemonade out of lemons.