Yeah, I think the same but if we can believe this, Ozzy was sober at the time and this was the main reason.
Ozzy: "Zakk came in at the beginning of the new one, but he was still drinking. When you're drunk and somebody else is drinking, it's okay, but when you're sober and somebody's blabbering away in your ear, it ain't. I mean, Zakk's a great player and I love him. I love his playing. But in the end, it came to the point that I had to get another guitarist. Not because I fell out with Zakk, but it was hard for me to be around someone who is actively drinking. "
But Ozzy has treated so many musicians so bad and he complain how bad Tony treated him in BS.
Ozzy is not perfect at all but I think Sharon is the main reason all of this.
Yeah, Zakk overuse the p.h. but it less annoying to me (he makes the "good type" of p.h. plus his vibrato is proper) than Kirk's super fast "mosquito vibrato".
(Don’t get me wrong: among other things, I learned to play guitar (somewhat) on Metallica songs and without Kirk’s solos it wouldn’t be the same the Unforgiven, Master of Puppets, but his riffs led to songs like Enter Sandman, Creeping Death, Trapped Under Ice, he also brought several riffs to the Master record, etc.)