I know this is a bit of a wanker's comment, but Oasis stopped being everything that made them special after they'd made it big. The energy, the working class angst, the voice for a generation stuff was real, but the lyrics went hollow after they were millionaires, nobodies fault, just took the edginess away. That said the rivalry with Blur, although completely manufactured, was something not seen in UK music since and I don't think you will again, due to the way it and other media is consumed so as a social phenomenon it's historic
I saw them once after the release of Definitely Maybe and at Knebworth, probably the best and worst gigs I've ever been to. Anyone that tells you the Sunday was good were either off their faces, not there, or lying. Part of that situational - literally hours to get food or drink, the line up wasn't as good - Kulashaker ffs and Liam was off his tits, some may find forgetting the lyrics to Champagne Supanova endearing, but I didn't.
I guess as a cultural phenomenon it'll be something - probably the biggest band in the UK of the last 50 years playing together(ish) for the first time in nearly 20 years, but so was Taylor Swift and I didn't have any desire to see her either.