Is Jonas Kaufmann really an exceptional tenor?

Don't hold your breath, JKH. He has not become a great Florestan yet.

What about a potentially competitive Lohengrin or Tristan? I cannot bet on that either.

Why does he need to wait another ten years before tackling Tristan? Does his voice need to mature further?

I can understand your reasoning. Thank you for the explanation.

I've just been listening to Sehnsucht on Kauffman's Strauss disc for Harmonia Mundi. Overall, I like the voice. However, he seems to have a bit of a problem when transitioning from his middle notes to high notes. The best way I can describe it is the impression that you can hear him going from one gear to the next. What I mean is that the transition isn't seamless and smooth. Since this is an early disc, maybe his technique has improved since then. Any thoughts?

It's absolutely on-topic, Parisboy, and a very interesting subject. And yes, male voices certainly can develop wobble in just the same way as their female counterparts. As a general rule of thumb, the more solid and secure the singer's technique is, the less prone to wobble he or she will be, though age and nature play significant parts as the singing mechanism becomes less elastic and responsive. This often manifests itself in a sort of slow, steady beat in the voice on sustained notes, and can often be exaggerated by recording.

Samuel Ramey is an example of a modern singer with an immaculate technique, but in some of his later appearances and recording (try, for instance, his Naxos recital) the beat in the voice has been very prominent indeed. Going back a bit, the last recordings of Lawrence Tibbett show what abuse and overuse can do to a voice in this context. They do not make pleasant listening, but I think illustrate the point.

I certainly detect not the slightest hint of anything to give concern about Kaufmann, whose technique appears rock solid to me. There are very few dramatic tenors I can think of who are as able to sing such wonderfully floated pianissimi. No guarantee, of course, but things look very promising, to say the least.

The point you make about equalisation of the registers is, of course, something that's the goal of every singer and singing teacher there's ever been. Some voices are absolutely seamless (Bjorling, for example) whilst the break in others is more obvious (for my money Pavarotti, though not all agree). I think with heavier voices, such as Kaufmann's, it can seem emphasised because of the contrast between the 'baritonal' weight of the bottom of the voice and the more brilliant tenor top.

Ramey and Hampson are in a sad state these days.

That being said, he sounds convincing when singing the Mahler lieder from Des Knaben Wunderhorn. That is my only recording of his other than his Lied von der Erde under Rattle with the CBSO. He doesn't seem to be putting excessive weight on his voice in these recordings. His tone is on the contrary light and appropriate for the lieder, his phrasing elegant and in good taste. These recordings are from this 1990s however. I haven't kept up with his development of his voice lately.