From the New York Times:

If the name of the American soprano Deborah Voigt is attached to any one thing, it is the title character of Richard Strauss's "Ariadne auf Naxos." It is her signature role, the one that shot her to fame when she first performed it 13 years ago in Boston. Her Ariadne at the Metropolitan Opera last year prompted Anthony Tommasini, a critic for The Times, to praise her "arching lyrical beauty" and to add, "She was at once truly grand and amusingly self-deprecating, striking deadpan poses that any Broadway actor would envy."

Little of that seems to have mattered to the Royal Opera House at Covent Garden in London, which is producing the Strauss opera in June. It replaced Ms. Voigt – a large woman even when her weight fluctuates downward – with a slimmer and lesser-known soprano who not only fit the casting director's vision of Ariadne, but also fit into the little black cocktail dress chosen for the character.
Opera fans are used to extending their senses beyond seeing a body on the stage, which is but one piece in a pageant. It's the musicality that matters.

But as audiences are graying, opera houses are looking for ways to pack in a younger crowd. Casting directors trying to make opera hip may be turned off by "big hips," like those Ms. Voigt admits to owning. In this case, the decision will deny British audiences an opportunity to hear and see a performer who may be at the peak of her powers. Her voice may be perfect, but at least for Covent Garden, she's too big a star.

It's not my argument. I won't be going to Covent Garden no matter how slim the sopranos. For me, it's just not worth what they charge, and even if they were to try to loss lead me into that place, I'd still be reluctant. Live opera is a habit, and not one I can afford.

I found the Deborah Voigt picture here.

I wonder, is a (small) part of the reason fat ladies are no longer attractive that a strong female voice, in the age of microphones, counts for so much less these days? Probably not. But I am struck by how important, historically, the ability of females to make music influenced the ability of females to get husbands. On the other hand, an industrial strength, opera-house-filling soprano is not quite what pre-hi-fi Husband would have been looking for.

No, the real villainess, from where Ms. Voigt stands, is this spectacular looking lady.