I’ve recently had an epiphany that took me 37 years to arrive at. After decades of having either Maiden or Metallica ranked as the greatest metal band, I’ve concluded that after listening to their discography pretty much daily for the past 6 months - Judas Priest is the greatest metal band of all time, ahead of Metallica, Maiden, and Sabbath.
That trio of Halford, Tipton, and Downing is easily the greatest trio in metal history. Maiden checks all the boxes except the heaviness; their riffs are seldom very crunchy. Metallica doesn’t have the quantity or vocals to compete, though their peak is equal to Priest’s. Sabbath is a different animal, a lot of quantity but as with Hetfield, Ozzy’s vocals can’t compete. First 6 Sabbath albums plus the Dio ones make it a competition but I much prefer the more modern sound that Priest perfected in the late 70s and onward.
I put Maiden at the top because the point that "Maiden's riffs are seldom very crunchy" is far less important to me than it seems to be to you. Also, while Halford/Tipton/Dowing = Dickinson/Murray/Smith (and MIGHT BE slightly >), when you throw bassists into the mix, it's no contest: Dickinson/Harris/Murray/Smith >>> Halford/Hill/Tipton/Downing.
For me, it's a razor thin margin between Maiden and Priest, followed by Metallica. Sabbath is classic, but they don't come close to the other three.
Vocals: Priest/Maiden-Sabbath-Metallica
Riffs: Metallica-Priest-Sabbath-Maiden
Leads: Priest-Maiden-Sabbath-Metallica
Drums: Priest-Maiden-Metallica-Sabbath
Live: Maiden-Metallica-Priest-Sabbath
Bass: Maiden-Sabbath-Priest-Metallica
Quantity: Sabbath-Priest-Maiden-Metallica
Songwriting: Priest-Maiden-Metallica-Sabbath
Popularity: Metallica-Maiden-Sabbath-Priest
These are rankings, right? Are you seriously placing Ian Hill above any of Metallica's bassists (or the three of them combined)? I don't have much of an opinion about Trujillo, but as much as I love Ian (just for being Ian), he can't touch Newsted, much less Burton.
Stadler spoke for me.
I love Judas Priest, I love them really a lot so I'm not just a casual listener but a very big fan, but - tastes and historical merits aside - Iron Maiden is as a whole way better than them, especially for the consistency. Even in the "year of the synths", 1986, Iron Maiden did Somewhere in Time and Priest made Turbo. And Maiden follow it up with Seventh Son, while Priest with Ram it Down.
It's only in 1990 that Priest blew Maiden and 95% of the rest away with Painkiller, but in the '80s Priest had been more inconsistent while Maiden's run from 1980-1988 is basically textbook "how to be the perfect heavy metal band".
Not responding to you directly, but just as a reminder, I'm not on the Painkiller train. If I had to choose I'd take No Prayer, even though that's a deeply flawed album and not a high point in the Maiden catalogue. Honestly, Tattooed Millionaire is probably better than both of them. It might be just me, but 1990 was a low point in metal. Other than Ritual de lo Habitual by Jane's Addiction (which isn't really metal) and Queensryche's Empire (which isn't really metal) that's not the year I'd point to for metal greatness.
I just looked at the 1990 list and, for me, there's nothing that comes even close to Painkiller. It was, indeed, a very bleak year. Anthrax's Persistence of Time was disappointing, Dio's Lock up the Wolves and No Prayer for the Dying were bad. I imagine some folks would point to Pantera's Cowboys from Hell, but I've never liked anything I've heard from that band. Half of Empire was really good, and half was blah (and, like you said, they were veering away from "metal"). On the other hand, Warrant put out Cherry Pie and, while I'm being facetious, I Saw Red is an EXCELLENT song.