Natasha, Pierre & The Great Comet of 1812 is a puzzle to me. Because the show is invigorating, original, and evocative and, yet, also overbearing in its intensity. Based on 70-pages of Leo Tolstoy's second volume of War and Peace, the Off-Broadway transfer, which features the Broadway debuts of singer Josh Groban (Pierre) and Denée Benton (Natasha), offers a sometimes annoyingly frenetic, immersive experien…