You keep saying this, but I don't really think it's true. I think that Blaze simply sings differently, like
@MrKnickerbocker once explained. I can certainly accept that the voice isn't for you.
Then short of getting an isolated vocal track and objectively measuring it, I don't know what would change your mind. It's blindingly obvious that he's off the note all over the place ("a lonely cry for help", "for help to anyone", "to help you on your way", "when I was happy", "to get on with your life", etc., etc.). If by "singing differently" you mean "warbling around different frequencies without caring which one you actually hit", then sure, I guess. But by that standard, literally everyone is a superb singer who just "sings differently".
I'm actually somewhere in the middle of this argument for this particular song. I do generally think that Blaze has a very specific quality to his voice, something in his timbre, that can make him sound like he's wavering around certain notes. I'm not sure if this is actually a pitch issue or just how his voice sounds.
However, I do have to agree with
@Jer about some of the notes on Judgment of Heaven. The problem is in the ends of the phrases and I don't think it's just a Blaze problem, I think it's a problem with Steve's melody. First of all, the major scale is so intense that it is at odds with the incredibly dark lyrics and thus, feels weird when Blaze sings about unhappiness and suicide while trying to put feeling into it. Second, there are notes that are sliding around at the end of the phrases "on your waaa-ay" and "mooo-ore" as if there's a small pull-off or slide on the guitar melody (how Steve wrote it, I'm sure).
I recorded some examples of the melody along with Blaze's tracks, turning Judgment of Heaven into one of my
most favorite kind of Iron Maiden arrangements: guitars playing the vocal lines along with the vocals! Here's the original:
https://drive.google.com/file/d/1WmghR-IrsYAV58IX6zrsbuGNJhDSAjYI/view?usp=sharing
Hear how Blaze's vocal wavers on those two words along with the guitar? It's a problem with both his vocal performance and IMO the melody itself. He grew into his voice more in his later years and I think sounds much better on the acoustic version from 2 years ago with Thomas Zwijsen. Here's that performance with the guitar melody overdubbed:
https://drive.google.com/file/d/1RHf9tniZwY9-NDjUZ20f9rZu_ZjBUDsz/view?usp=sharing
His now lower voice can slide easier and he throws more breath/talk-singing into it to make it less sing-songy, which really helps the overall performance. I still think the melody is silly and could be better by adding a blue note into the mix, so I recorded a variation on the melody over an instrumental track I found online:
https://drive.google.com/file/d/1TbMrpY_Txir32LcObXRFXpKqPt9sWFqN/view?usp=sharing
Changing a couple notes on the first and third lines as well eliminated that half-step slide on lines two and three would, I think, actually work a lot better with Blaze's voice (as he has a tendency to dip around some pitches if the melody isn't 100% rooted). But, oh well, we'll never hear him do that and who am I to say my melody is better than Steve Harris'?
Now,
no one ever ask me to analyze Judgment of Heaven ever again.
