I am from the old school where you each note of the song was sung with a few variations. As the years pass musicians and singers began to add more and more to a song until it was no longer the song.
This is acceptable if you listen with a Jazz ear. Musicians added more scale and scales modes. My preference is to add notes and scales without losing too much of the melody. It was a dance in a New York hotel, about 175 people. We had a drums, sax, bass, a portable B3 organ, and myself on guitar. The sing, Witchcraft in F. The sax who was real good took his improvised solo. I think he was playing over the chords. We went into the second song, same key and tempo. After my vocal the sax started his impro solo. He was good. He suddenly turned to me and said, “What song are we playing”.
At the Sands hotel in Vegas – Ethel Merman (Spelling) was singing – Sinatra was in the next room. I’ll never forget his choice of words. “Hey, who’s yellen’?” I love it.
All music has its place, John C.