MFL. I have never seen a production of Carousel in which I did not get a little bored at times (and that includes the last one at Lincoln Center). Amazing highs, but definitely lows. I don't think any decent production of MFL has much in the way of lows, and I am expecting this one to be stellar. Can't wait to see what Sher does with that stage, especially in the opening number in Covent Garden and at Ascot; he creates such memorable moments in that theatre.
Re O'Brien, I can't think of major director with as inconsistent a track record as he has. He had career highs with the epic drama, The Road to Utopia, also at the Beaumont and with Hairspray, but he also had a string of misses, several of which were disastrous IMO. Charlie and the Chocolate Factory, The Times They are a Changing, and Catch Me if You Can -- all fairly recent musicals -- fit the disaster moniker IMO, and I would assign a sizable portion of the blame to him.
Also, I have not seen anyone comment on the logo being used for Carousel, but I find it incredibly dark; looks like something they'd use to advertise a Guillermo del Toro movie. I will definitely wait for the reviews (or at least message board feedback) on that one.