I'm going to differ with you and say that Dawson was a great singer with something less than a great instrument. I really did enjoy this, but a bit more "opulence" of timbre is important to me. I know it's a subjective preference, but for Iago? Darkness and weight of tone really is needed. I can't believe Dawson is evil; just set him alongside, say, Gobbi. A difference of "Night and Day" (Dawson could sing that quite stylishly, don't you think? With a little Noel Coward attitude?). He has a veddy British sound, to my ears - sort of reedy. No offense, but I can't help visualizing G & S when I hear him.
"Batti, batti..." (I'm covering my head).
Interesting that Dawson and Gobbi were both unusually versatile singers, yet each projected a certain persona that suited some kinds of music very well and seemed slightly out of place in others, even while they sang very well. I've heard Gobbi in lighter music such as Tosti's Ideale where his voice seems a little too dark to be suitable, as if a certain villainous/antihero quality which he uses to very good effect as Scarpia/ Iago/ Rigoletto is inherent in the timbre of the voice itself and can't be put aside just because it is unsuited to the material currently being sung. Dawson has a similar yet opposite problem in the Credo: the character is villainous but he sounds hearty and likeable, which is arguably appropriate for the Iago who is dissembling in the presence of the other characters but inappropriate for a soliloquy in which supposed to be revelling in undisguised villainy. Of course, I am not discounting the fact that Gobbi, while he could not change the basic timbre of his voice, was a distinguished operatic actor whereas Dawson (his turn as 'Hector Grant' aside) was content to be very much himself in everything he sang.
To the extent that I'm any kind of connoisseur of singing, two British (according to a broad definition of 'British'!) singers are responsible, and they are Peter Dawson
and John McCormack.
Both recorded popular material prolifically, and their records were the first records by great singers that I encountered (before I had heard any opera or 'classical' material), and together they set an incredibly high standard of baritone and tenor singing which the most celebrated continental and American singers should be held up to. To this day, I think that all baritones and basses chantantes should be subjected to the Peter Dawson test: can they sing the Largo al factotum, or Schubert's Erlkoenig, or Honour and Arms (or whatever) as cleanly, easily and elegantly as that great and underrated Australian bass baritone did? There is of course nothing wrong with associating him with his core repertoire of G&S, rousing patriotic songs etc, which were to him what Verdian and Puccinian villains were to Tito Gobbi. To get back on topic, sort of, Dawson has comprehensively 'ruined' the song repertoire associated with him for any other singers. I can't listen to anyone else singing 'The Fishermen of England' or 'The Road to Mandalay' (I hope Wood forgives me for secretly enjoying such obnoxiously rightwing, imperialistic songs as the latter, but it's an amazing Dawson performance nevertheless.)
PS If you find Dawson too reedy, you may enjoy Robert Easton
. He came the closest to 'ruining' Gounod's Mephistopheles for me, in the English language recording conducted by Beecham in 1929-30. He has the elegance, the poise, the beauty of voice, but I was hoping for a little more thunder and rumbustiousness in 'Le veau d'or', where he is rather too well mannered (as was Plançon). Youtube has his 'Vecchia zimarra' from the complete Act IV of Boheme, which shows off his beautiful voice and tasteful singing, the latter always a relative rarity in Puccini:
Here he is in the Peter Dawson repertoire- a setting of the Kipling poem 'Boots', frustratingly lacking the last few bars.
And here is Dawson himself, so we can decide whether he has in fact quite 'ruined' the song for the more opulent voice of Robert Easton: