Personally I really do hope U2 do put all their energy into creating a huge show on the next tour - they have a reputation as one of the premier live acts always at the fore of new technology, they should try and serve it. Having been introduced to the band by being blown away by watching a video of Zoo TV, I think they should strive to out do it. But at the same time I understand why people believe they've been there, done it, and should focus on the music instead.
As well though its what the band desire. We know Bono says the reason they place such high expectations on themselves is that it has to blow their minds as well as the audiences - well, for a band who have put on Zoo TV and Popmart, it must be pretty hard to blow their own minds as well in terms of the show and spectacle.