The reason people are negative about this tour is because Ozzy is involved. No matter how many years of great performances he has given us people still find the need to be negative towards him because he's a hit and miss live singer and he's canceled shows in the past because of health issues. I guess everyone would rather Ozzy perform while he's ill and risk dying on stage instead of canceling shows so he can get healthy. Plus, you add that Bill isn't part of the reunion and Tony fighting cancer, there's a bit of a negative vibe surrounding things at the moment.
Still, anyone seeing this tour should be extremely happy that despite the health issues and whatever else is going on, we've got three men up there in their mid 60s giving the best performances they can possibly give. They could've easily said "fuck it, we're too old now" but they reunited and came out with a great new album for us fans who have been waiting a long time for this to happen.