Personally, I had no problem with the tree or the set. I wouldn't say that the show was scenically at the top of Prince's work, but it was fine. The staging was excellent.
I found Brent Carver a bit too mannered. I wished I could have gotten to see Don Stephenson, the understudy. I heard he was excellent from a friend who saw both. And I wish I could have seen David Pittu on the tour.
I wonder if designing for the thrust stage of the Beaumont made the set less striking than it might have been had it been designed for proscenium. Perhaps they were somewhat limited in what they could do without screwing up the sightlines.