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Huge dinosaurs?
The writer and theatre director has called the industry's big names "huge dinosaurs" who arrive "with shreds of primeval vegetation hanging from their jaws".
Top singers 'inflexible'
The complaints highlight what he perceives to be uninspired delivery from ageing stars.
Dr Miller, who has also directed several well-received productions including Cosi Fan Tutte at the Royal Opera House, avoiding name any specific performers in his interview with Classic FM Magazine.
But it appears that his comments were directed at top names on the circuit, possibly including The Three Tenors who make brief star appearances at the major opera houses.
Audiences under attack
Dr Miller also criticised the new audiences which have been attracted to opera by these populist performers, saying they know little about opera.
He dismissed the growing army of fans belonging to Luciano Pavarotti, Placido Domingo and Jose Carreras as "an audience of the sort that applauds when the curtain goes up".
His comments may prove controversial for Classic FM, a radio station which has aimed to make classical music, including opera, more accessible to a wider audience.
Nick Shave, of Classic FM Magazine, said that the comments were likely to create some lively debate among the magazine's readers.
"I think it's an interesting view, and one that our readers who like this sort of music might find controversial. But I am sure they will believe that there are other points of view to be listened to," he said.