Proposed changes to “Porgy and Bess” before its Broadway revival range from replacing recitative with dialogue to brightening up the ambiguous ending. Supporters say this new, “Bess-centric” version fixes the original opera’s thematic problems. Detractors, including Stephen Sondheim, complain of disloyalty to Gershwin’s classic. (Check out this link to The New York Times: What do you think?