I would absolutely love something like 21st Century Breakdown again just one more time in their career. The incredible production, the wide variety of instruments and arrangements, Billie Joe's vocal range, etc etc etc. An unbelievable record start to finish.
How did that come to be? The band feeling adventurous after American Idiot? Warner/Reprise asking them for an epic follow up to American Idiot? Butch Vig's touch?