Ideally, I would like a bit of both to happen within the same tour leg as per The Joshua Tree tour.
I love seeing the band up-close in an intimate setting, it's always of preference to me. But stadium's have their advantages too in the fact that the show can be a bit more spectacular, and hold anything up to ten times the capacity of an arena, meaning more people get to see the band.
Maybe its too difficult logistically for a band of U2's size to do both these days, I don't know, but I think everyone would be happy. I remember reading earlier this year that their was a difference of opinion within the band, Edge & Adam want to do an indoor tour, whilst Larry & Bono want to do a stadium tour.
It would be really amazing if they could do a handful of secret unannounced club gigs during the tour under a pseudonym a la REM as 'Bingo Hand Job'. Maybe one per country.
It will be interesting to see what kind of stage setup Pete Williams and the band come up with. I think the heart was the ultimate/ideal stage setup, but I don't imagine they'd use it again, although I'd be happy if they did
An in the round show would be very cool, but again, I imagine logistically they can be a total nightmare.