That may sound like fun at the moment, but ive been thinking and i bet 10 years from now u2 has some type of technology that makes the claw stage look like a small barn by comparison. I suspect there will still be a massive stage centered in the arena, but out of that stage expect hovering b stages that can float around the stadium so that during different songs the band might be playing physically right up in the nosebleed section, or wherever they chose. Of course, the main stage will have the drive in movie screen for the rest of the audience to watch the action.
U2020: The Last Tour on Earth. Fire and Brimstone, guys, lots of hits, coming to a stadium near you to coincide with the end of the world. Only the people who line up for GA 6 weeks in advance will get to the promised land, everyone else will perish post concert apocalypse. Who'd ever have thought Armageddon would look & sound so good?