The plot certainly didn't need the romance, but musically -- maybe. The son had a big aria early in, which the tenor playing the role sang with passion. For my money, the best voice on that stage belonged to the plump lady in the tacky wig. Her mezzo was mellow and distinctive, more pleasurable to listen to than the leading lady's occasionally screechy soprano. I don't know any of those principal singers; in his intro, Eric Owens said they were all "famous Slavic singers". Probably not too many other singers know those roles. But the multi-race chorus was strictly the Met's own.