Late comer to the discussion but finally signed up to join you in your assessment of the greatest opera artist of all time. See either of my arguments (a double posted comment, which the first of I cannot myself delete). When others disagree based on their taste for X singer's voice, they know they're not being logical in their assessment. Perhaps they offer their opinion as a de facto acknowledgement by evasion that Domingo is the greatest, for they can't bring themselves to so say out loud? That's a pity.
One point of disagreement, however; you say:
Domingo has had to work hard to conquer the vocal challenges of the roles he has sung. His voice is as close to the heavier German heldentenor timber as a Mediterranean voice gets, and he has never been able to master the high C, the holy grail of tenor goals. But he has as good a high B as any tenor, and he has learned how best to take advantage of his natural gifts and to overcome the lack of agility that restricts many dramatic tenor voices.
Actually, he did (until at least 1998, and I might add, squillo (ring)) in fact have a high C, and I might add, D and F. Yes, He produced the high C many times, in live performances, early on, and the occasional high D (something even the WaPo Critic Midgette has proof of (Washington Post, Entertainment, 1oct2011. "I have admired Mr. Domingo tremendously as a singer since the dawn of my operatic consciousness: his "Otello," his Cavaradossi, his Arrigo on the recording of I Vespri Siciliani (complete with a high D, thank you very much.)" (emphasis added)
There are those, usually his detractors, who make the no high C claim without supplying proof because, in the case of the innocent claim maker, likely they heard him say he had no high C in a guest spot on The Tonight Show. If you don't know Domingo, you can't be faulted too hard for taking him at face value. But once you do know him, you realize he was joking at his own expense. Bafflingly, the tendency for far too many to hyper-focus on that lone note tends to reduce the rest of the aria to mere foreplay. And it's vandalism of the piece when the composer did not write in a C (e.g., Di quella pira). Bad habits die hard.
The witting no high C claim is a lie repeated by Carusians, Krausistas and Fat Lucy fans. The Pav is who crowned himself, by way of Breslin, the King of the High C. Pavarotti lost his high notes far sooner than he should have, likely in no small part to his habit of dispensing them indiscriminately at concert after concert, per the Breslin doctrine.
This place is a refreshing pool of actual thoughtfully written and reasoned essays, that it makes most other blogs pitiable in comparison. Your's on Domingo featured a dose of bold conviction, which makes it a bracing read. Must be why it remains a web engine search favorite to this day.
I'll close by asking... have you heard Domingo sing Tristan? Recorded 2005. There's a great review over at musicweb-international.com. His Act 2 aria, which starts at O Konig, das kann ich dir nicht sagen, leading to the hauntingly beautiful Wo Tristan geht, wird Isolde folgen is transporting.