“Whipped cream and knives,” is how Hal Prince once described the tone of A Little Night Music. And I can’t judge the cast based on a first preview, but I’ll say this: There is no whipped cream in this staging. What hurts is what can’t be changed: a dark and oppressive set, curiously dim lighting, utterly forgettable costumes. The music is sublime because the music is sublime (ah! The Sondheim Tautological Principal!), but there’s little color on stage—literally, anywhere, and no hint of a spark. And that elegance? That irony? That magic? That bubbling and sad, lighter-than-air bewitching thing that’s the essence of A Little Night Music, that sends you dancing out into the night, spellbound and awestruck and closer, somehow, to the sky? Maybe when I go back in December it’ll be there.