Pardon my going offline for a few days. I've added a few links to my initial review.
Some points I neglected: First, I think the chorus did well in the unsympathetic production, which mostly uses them as a static, monolithic bludgeon. They do get to sing the opera's big tune, which unfortunately -- as others have noted -- isn't that memorable. But it's the proto-fascistic ritual chanting of the beginning that's most striking.
Second, it's true that some very successful operas have covered very little overt action or drama at all, including several of my favorites (Bluebeard's Castle, Pelléas et Mélisande -- both discussed previously here). But these pieces use a refined and highly cohesive text and musical language to magnify the inner happenings that are on show. The First Emperor isn't concerned with interiors period; doggedly public, its characters are unindividuated, seemingly by intention. Yet its language and thematic content is still a scramble, and Tan Dun's polyglot score is far from the masterpiece of drama and cohesion that could make sense of the evening on its own.
Third, I agree with Tommasini's critique of the work's one-dimensional handling of vocal lines.
Fourth, I also agree with Lisa Hirsch that Wagner and Mark Adamo have been successful as their own librettists. (Adamo's adaptation of Little Women into a successful piece of theater is brilliant.) But of course pure foolishness does sometimes get things right...