No; unfortunately I never heard Vickers or Nilsson. Domingo came over pretty well, particularly as Radames, Dick Johnson and even Siegmund when I heard him; he never really had a top C - at least, not for long - and yes, he started to sound pinched in the higher regions quite early, hence his ill-advised transition to "baritenor". You set me thinking and I realise that I heard other great voices whose like are long gone: Rita Hunter, Carlo Bergonzi, Rosalind Plowright in her soprano phase, and Angela Gheorghiu at her best. Some whom I thought were wonderful are now comparatively neglected, such as Anthony Raffell as a great Wotan with Linda Esther Gray's superb Brünnhilde at the ENO, Very few singers of the last thirty years are on their level, I think.