I'm ambivalent about a Sabbath reunion. That would be true with the original lineup or even with Dio.
I'm not sure what they can add or what mystique they can draw from it. It seems contrived versus a real reconciliation or 'something that needs to be done for resolution'.
I don't know that I'm articulating this well.
Think of some recent reunions that were (IMO) magical:
Cream reunion. Cream is greater than the sum of the parts. There was bad blood there and the band was originally short-lived. There was a mystique there and a tension that seemed to fuel the reunion. Whether or not you like Eric Clapton is irrelevant. Footage of Royal Albert Hall concert is 3 amazing musicians playing and they sounded great. The fact that the band hasn't existed for decades was a draw. It was like bringing out King Tut for exhibition.
"Led Zeppelin" at O2. Simply amazing concert. The fact that they hadn't worked together in that capacity for so long fueled that, plus everyone was "on".
Van Halen with Dave. Meh. But, it worked for me. It would have been truly magical with Michael Anthony on bass. Still greater than the sum of it's parts.
I love old Sabbath, but I'm kind of bored with Ozzy as a performer these days. I wonder if they should leave well enough alone. Not sure if greater than the sum of the parts. Maybe I'll be pleasantly surprised.