Billy was doing most of the work regardless... just because Vig and Flood were producing doesn't mean they made it sound the way they did. Otherwise they would have a lot of other albums with that kind of quality and they do not, period.
Have you looked at Flood's production credits? He's produced, engineered or co-produced some absolutely fantastic albums. I'd certainly put it up against Corgan's who's studio output has been dire for over a decade.
Nick Cave and the Bad Seeds
##From Her to Eternity (1983-1984)
##The Firstborn Is Dead (1984)
##Kicking Against the Pricks (1985-1986)
##Your Funeral... My Trial (1986)
##Tender Prey (1987-1988)
##The Good Son (1989)
##The Boatman's Call (1997)
Erasure
## Wonderland (1986)
##The Circus (1987)
##Loveboat (2000)
U2
##The Joshua Tree (1987)
##Achtung Baby (1991)
##Zooropa (1993)
##Pop (1997)
##How to Dismantle an Atomic Bomb (2004)
The Silencers
##A Blues for Buddha
Nine Inch Nails
##Pretty Hate Machine (1989)
##Broken (1992)
##The Downward Spiral (1994)
Depeche Mode
##Violator (1990)
##Songs of Faith and Devotion (1993)
Pop Will Eat Itself
##This is the Day, This is the Hour, This is This (1988)
##Cure For Sanity (1991)
The Charlatans
##Between 10th And 11th (1992)
The Smashing Pumpkins
##Mellon Collie and the Infinite Sadness (1995)
##Adore (1998)
##Machina/The Machines of God (2000)
PJ Harvey
##To Bring You My Love (1995)
##Is This Desire? (1998)
##White Chalk (2007)
##Let England Shake (2011)
Nitzer Ebb
##Belief (1989)
##Showtime (1990)
##Ebbhead (1991)
##Big Hit (1995)
##Industrial Complex (2010)
JJ72
##I To Sky (2002)
The Duke Spirit
##"Cuts Across The Land" (2004, released 2005)
A-Ha
##Analogue (2005)
Soulwax
##Any Minute Now (2005)
Placebo
##Meds (2006)
The Killers
##Sam's Town (2006)
Sigur Rós
##Með suð í eyrum við spilum endalaust (2008)
30 Seconds To Mars
##This Is War (2009)
Editors
##In This Light And On This Evening (2009)
The Pains of Being Pure At Heart
##Belong (2011)