Although I agree, I don't think Gaiden Shinji was famous for that quote. I think it's more likely the quote was famous because of Gaiden Shinji.
On a related note, I'd think people like Gaiden Shinji, the hero from Daggerfall and the Nerevarine aren't Champions of Cyrodiil. The reason being that their actions had very little to do with saving Cyrodiil (excepting the Nerevarine, who did so indirectly).
I seem to remember that the bottomline position on the Nerevarine, Dagoth Ur and the Blight was that if Dagoth-Ur did defeat the Tribunal and conquer Morrwind, he would create an unstoppable army using the Blight and so the Blight would sweep over the rest of Tamriel plunging it and likely the other continents also into darkness forever.
Against that we have the low-key way in which the Nerevarine was introduced into Morrowind ...
I think I agree that the Nerevarine was not one of these so-callled Champions in the Imperial mind - but not because he did not earn it.
Likewise with the chamiopn of the Spire - last of the Imperial Battle Mages (or was it the other kind of mage you became if you succeeded?) the invasion of the Battlespire was not merely about depriving The Empire of a training school and embarassing it. What was intended was to create a secret beach-head in preparation for a far more extensive invasion - maybe the opening of the Gates was delayed while the Tribunal and Dagoth Ur dealt with each other - otherwise the Battlespire might have acted as Dagon's HQ.
Btw - one suspects that the murder of the sleeping Dragons in the Battlespire was the reason Akatosh was so keen to smack the (censored) outta Dagon when he arrived in person - otherwise the Hero of Kvatch might have become the bloody smear on the pavement.
Could it be that the other 'Champions of the Empire' have been either Arena Winners, leaders of Imperial Armies or Emperors?