Dio is just one of those polarizing singers - like Ozzy, you either dig it, or you don't.
Sabbath/Ozzy = beefy
Sabbath/Dio = still beefy, but way more cheese
Probably because I can't EVER get into a band whose singer I just don't dig...Dio I'm just on the fence about, but for instance Maiden, I just can't stand 'opera metal' vocals and have taken a constant pass on it. I've read interviews and such with/about them, and I'm not saying Dickenson 'sucks', but I just don't like what the overall sound comes to.
I can see where the 'hair metal' thing comes in, fwiw...if you're a certain age, if it sounded anything like 'Sunset Strip Metal' it wasn't cool, and to this day I really just don't like most of it. Bands that leaned in that direction were to be avoided...hell I still don't listen to the first Alice In Chains album much because it sounds too much like Alice N Chainz

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I'd prefer 13 with Ward, but it wasn't a deal breaker for me - if he'd have come to the table looking for something more than money - like making a nice 'cap' for their careers and contribution to music, and a fitting goodbye to their fans - likely no one would be bitching at all right now. 5% doesn't sound like much but that was going to be 5% of a #1 album and tour revenues, and Bill doesn't write and classically hasn't written much of Sabbath's music, despite his 'secret sauce' contribution to the band's sound.
Zep used to offer 1% to concert venues - 'because you'd damn well want 1% of a Led Zep concert if you can get it'.
I was just reading the Nirvana RS special, and it mentioned that Nirvana's split was 75% Cobain, and 12.5% each for Novoselic and Grohl. So I don't see what Bill is after - maybe 5%? Considering Geezer's contribution to lyrics along with his role in shaping the music as it's jammed out, considering Tony's overwhelming contribution (no Tony, no Sabbath, no question), considering that Ozzy writes 1/3 to 1/2 of the lyrics, I don't see much room for Bill's share.
I love the guy and his drumming to death, and maybe it's slightly less than fair, I don't know. But so is taking your football and going home when your bandmate is battling cancer and you're lucky enough to all 4 still be alive to bicker - one can just ask Pink Floyd about the opportunity squandered for a final 'real Pink Floyd' album that'll never come to pass now.
Ideally, we'd have an 'original 4' album and who knows, maybe there's still time. I don't think it's all to blame on Ozzy and his 'evil wife' though.
Maybe it's just me, though, I had zero problems with Alice In Chains' post-Layne work, despite him being one of my big heroes...he's dead, and all one has to do is peruse the credits to the first five albums/eps and see who wrote the lion's share of the material...Jerry Cantrell. So, for me, the idea that Alice could go on without Layne doesn't offend. Particularly since the resulting sound is so spookily accurate.