Have to agree with you there, Richard. I don't wish G4 ill, but all this over-hyping does irritate me. I'd never claim to be an expert on opera, nor do I deny that Jon has a good voice, but it sounds no better than several young tenors I've heard sing with, say, English Touring Opera. That is, it's probably good enough for a second (or third)string opera company, but there is a significant difference between that and a world class voice. Those are very rare.
Unfortunately for Jon, by singing Nessun Dorma, he inevitably invited comparisons with Pavarotti.