I have always been enamored of these more "operatic" style rock lead singers with strong tenor voices - the aforementioned, as well as Geoff Tate (what do you think of him?). I always counted James as one of them. They are all non-human, in fact I see them as angelic beings of a sort (how's that for love-driven hyperbole? ).
That said, it is tempting to compare singers between genres because as we know, the voice only works one way. I've been guilty of this too (having in the past described how a classical singer changes repertoire as they age, for example a coloratura soprano in her youth who gradually switches to more lyric soprano repertoire ::raises hand::). Coming from a classical background, but loving rock and metal, I couldn't help but fall in love with these singers. It's as if they cross the boundaries of space and time to create something so uniquely gorgeous in its unlikely combination (and some of them do have classical training, like Geoff Tate).
Okay, I am a singer. I am NOT professionally trained, and to all of you who are, my opinion wouldn't mean a thing in the discussion of how a person sings. But, I am a historian of Queensryche, and helped write their only biography, so I have a pretty good understanding of Tate's history as a singer, and what he does. My wife IS a professionally trained singer however. So she has dumped some commentary in my ears over the years, not only to help me get better, but to understand the complexities of voice.
Proud husband moment -- she had a short-lived metal project called Trans World Tribe. You can check her out doing some originals and covers here -
https://transworldtribe.bandcamp.com/album/defiance-e-p(my favorite original is "Roller Coaster" and I LOVE her cover of "Hallowed Be Thy Name" - eat your heart out Bruce!)
Regarding Tate, he was trained by the late Maestro David Kyle. Like many of the Maestro's students, he had a way of teaching his students how to "push" their voice in a way that is very much debated whether it is healthy or not. But, Tate's work with David Kyle didn't last long. He took lessons, got the basics, and then did his own thing. Tate's status as a tenor or baritone has also been a bit of a debate. I always thought he was a tenor, and then after people showed a lot to me, changed my mind. But there is no debate (for me) that during his prime (1983-1992), while his range declined, his voice was absolutely powerful, rich, and he had excellent control. Probably the finest combination of all those following Freddie Mercury and Steve Perry, imo. Tate, in a way, created a style of singing. Not completely, because everyone is influenced by each other. But when I was doing my new book on Queensryche (see the QR thread for more on that) that is coming out in March/April this year, I spoke briefly with Michael Kiske of Helloween, who certainly was blown away by seeing QR in 1984 and what Tate was doing as a singer. Dickinson was blown away by what Tate could do live...stuff Bruce couldn't do without a lot of effort, Tate was just doing.
While Tate may have declined a lot over the years, with smoking being a factor, age, alcohol consumption, etc., I still think his prime as a vocalist is probably THE voice in hard rock/metal for that period. No one other than Mercury or Perry, from 1983-1992, could touch Tate. And since QR was generally considered heavy metal from 83-88, I'd argue that Tate was the "best" or at least most gifted METAL singer of that period.
Over the years, as my wife has observed, Tate's technique got sloppy, then better, then sloppy, etc. It's clear he's worked at his craft again over the last several years. But his range in his head voice is very limited these days. He uses falsetto to hit the high notes, which he only experimented with in the past (he tried it in the 2003-2005 timeframe, abandoned it, and now is doing it again much more convincingly). Sorta how Halford used to use his head voice to hit high stuff, and now he's mostly falsetto.
Anyway, just some rambles from a baritone cover band singer who got some applause doing 90s stuff, who absolutely loves tenor singers.