Just a thought.. if Dio had been first and Ozzy second, would any of us still think Ozzy suited the band so well? I'm not concluding anything from this, just trying to get opinions out of you people.
That said, I don't care whether Ozzy has any vocal talent whatsoever. Talent isn't the be-all-end-all deciding factor on whether music is worth hearing, at least for me. Ozzy's uniqueness and emotion are what made him such an integral part of Sabbath. Ozzy WAS Sabbath, and no matter how good the albums written after he left may be, they will never be THE classic Sabbath.