Domingo sang the tenor version, didn't he? I thought the French version was baritone and the German was tenor. I don't know this music at all, but in that beautiful duet toward the end that Oreste and Pylade sang (arguing about which one of them should die), every time they harmonized, Domingo took the lower vocal line. Was the tenor version written that way? Or was a little switch made to accommodate Domingo's illness?
I agree about the staging; it was terrible. And I am so tired of the Met's monochrome sets. The acting could be called "failed stylized"...someone would strike a pose and hold it forever. So many times Susan Graham would stagger across the stage and collapse against a wall, where she'd stand heaving heavily until her next cue. Well, she had to do something during those long stretches when she had nothing to do. But surely the director could have come up with something better than "Go over there and heave, girl!" Still, even sick, she sounded better than I've ever heard her before. And, even sick, Domingo came through, but he did let a healthy Paul Groves steal a couple of scenes from him.