Hordes of Metallica fans claim that the band's 1989 performance in Seattle was the peak of James Hetfield's vocal ability.
Really? It's energetic! I'll give it that, but is "energetic" the sole measure of great rock vocals?
I'm going to posit that what a lot of people love about this special type of singing is really the byproduct of Hetfield's failure to understand and apply the basic principles of good breath control.
Did you ever wonder why he has no vibrato? Developing a natural vibrato requires a certain consistency of airflow.
Do you notice how many of his notes get abruptly chopped off instead of being able to resonate and ring out?
How about the habit of ending phrases with a sudden expulsion of air into an "ahh"?
Breath control is the common denominator with all these things.
Also consider his posture. What do you think that does to his airflow? Do you see how low he has the mic set up? He has to bend his neck down at such an unnatural angle to sing into the microphone. It creates a kink in the pathway of his airflow. You don't want that!
He did learn. If you look at Metallica's live performance from Slane Castle in Ireland on June 8th, 2019, you'll see that his posture was far better. Hetfield had stopped slumping forward and tilting his neck down like he did thirty years earlier. It looks better and it works better. Win/win situation.
Things like that help explain why he was able to have the long career he's had. He quit drinking too. He developed discipline and used it to improve his vocal hygiene and technique.
If only he'd applied the same discipline to his vocal technique that he applied to the mechanics of his guitar playing, and done it from the outset of his singing career, I believe he would have become an exponentially better vocalist.