Goldman Sachs was under siege two years ago, but its clients have stuck with it. It tops the M&A advisory and ECM league tables, and when its clients want debt deals, it can do those too. Chief executive Lloyd Blankfein expresses pride at the firm’s stability. But although Goldman hasn’t undergone the soul-searching many competitors have endured while seeking out their new, post-crisis, Basle III business models, its universal bank competitors ask if Goldman’s focus is too narrow.