Sad to hear about the death of Renata Tebaldi (though I thought she was older than 82). I think the obituary makes too much of the supposed Callas-Tebaldi feud. The fact is that their repertoires were very different; Callas specialized in bel canto roles like Norma, Lucia, and early-to-middle period Verdi, while Tebaldi specialized in the later Verdi -- Aida, Desdemona -- and Puccini. Callas recorded some of those roles, but she didn't usually do them on stage. The only part that both singers were strongly identified with was Tosca, and Callas wasn't terribly fond of that part (she became identified with it almost against her will, because her recording of it was such a gigantic success). Callas and Joan Sutherland, who actually sang many of the same roles, would have made for a better feud, but the media either forgot to create one or didn't bother.
Tebaldi's recordings don't really give me a full idea of what her impact must have been, as a singer. The impact of a huge voice filling the theatre, which is not only huge but beautiful-sounding, is something that can't really be preserved on a recording; and that's what made Tebaldi so special to people who heard her live. Most big voices have either a not-very-attractive tone or else a "cold" sound (Birgit Nilsson); Tebaldi's voice was big and warm and attractive, and it must have been quite something to hear, especially combined with her idiomatic Italian style: Callas was famous for re-thinking and re-inventing the operas she sang, while Tebaldi made the best possible case for the "traditional" approach to the operas she sang. On records, Tebaldi's vocal flaws are more apparent, especially the pitch problems; but there are some very fine complete recordings with Tebaldi. Her second recording of La Boheme, with an all-Italian cast that includes Carlo Bergonzi and Ettore Bastianini, is probably my favorite recording of this opera; it uses a somewhat unusual recording technique whereby the orchestra is placed forward and the voices are farther away from the microphones than usual -- this sometimes causes voices to be drowned out a bit, but it comes closer than most recordings to preserving the impact of a big voice in a theatre (you can really hear the resonance of Tebaldi's voice, not to mention the fact that her voice is bigger than Bergonzi's).