This is the opera board...all roads (threads) lead to Callas 
Sarge

I usually read Scarpia with at least close attention and usually agree with him; however, he is right off the mark on this topic in every way. Perhaps he is just trying to ginger us up. Usually this board is a haven of pleasant discussion.
Back to Janowitz. Again, I think we experience different things from the same sounds. She does have a cool voice and is majorly concerned with the beauty of the sounds, but I don't here her as either detached or bland.
In the main she has a terrific technique, though on the famous 'Creation' disc, on a Mozart Aria recital and in a live Don Giovanni, she evinces a weakness in one phrase or other in actually getting round the notes. I also have a live recital with a fast Handel aria and it is not a comfortable experience.
She certainly uses vibrato; if you can hear her in anything and find a boy soprano or Emma Kirkby to compare with, you hear the difference. What sounds utterly pure is a very carefully crafted sound, abetted by her very specific vocal equipment.
I always look for any surfacing performances, though did abjure a Karajan, Monteverdi 'Poppea' performance, that apart, I think I have about all her discs.
Despite promoting her, Karajan preferred to encourage her to use her voice in an instrumental way. He loved her voice and the sounds in abstract. A different mentor might have brought out more word painting. Very suddenly, he moved from her to Tomowa-Sintow, who once found, Karajan then used and excluded Janowitz. I never much enjoyed Tomowa-Sintow, her Karajan Four Last Songs is never now mentioned.
Recital discs recorded post Karajan show she was involved in the storytelling and emotional content of the songs.
Mike