For all the controversy that has surrounded Diane Paulus' revisionist Broadway revival of 'Porgy and Bess,' or, as it now is billed, 'The Gershwins' Porgy and Bess,' the considerable strengths of this production, which opened Thursday night at the Richard Rodgers Theatre, are in the traditional pleasures of witnessing a passionate, beautifully sung, richly visualized, splendidly played and indisputably well-intentioned 'Porgy.' This is a great American opera filled with breathtaking stakes, towering characters and a thudding naturalistic intensity. The considerable weaknesses don't really flow from cuts in the running time or the textual changes (the work of adapters Suzan-Lori Parks and Diedre L. Murray) designed to make this show more palatable for modern Broadway tastes and that famously aggrieved Stephen Sondheim, who stood in solidarity with the original librettist, DuBose Heyward, and preemptively howled against a proposed, but now abandoned, new ending wherein Bess returns to Catfish Row. They have all been overhyped and overdiscussed.