While nobody wants a rehash of Idiot, there are some cool things that could be brought back.
Kathleen Hanna and Jason Freeze could be featured again. Maybe give Freeze a temporary "fourth member" status.
Do we ever hear Tre Cool's 'backing vocals'? They need to be turned up in the mix and of course, the classic Dirnt harmony vocal has GOT to be a big part of the record.
Maybe a reference to the Boulevard of Broken Dreams in lyrics, but not the music.
and we all love when Green Day reuse lyrics from older songs to make song titles. So "I've Been...Waiting"
and
"Across the Alleyway"
mabye some "10 Cup of Coffee"
"Overwhelming Sensation"