Dictating a hierarchy in NBA history can be an exercise in futility. Splitting hairs between eras while drizzling on apparent subjectivity can create a lovely house for debate but doesn’t definitively provide answers…

LENNOX MCLENDON/Associated Press
1982 Los Angeles Lakers
W/L: 12-2 (.857)
ASM: 6.1 
OPP: PHX (46-36), SAS (48-34), PHI (58-24)
OPP W/L%: .618 
HOF: Dennis Johnson, George Gervin, Julius Erving, Bobby Jones
The Lakers dynasty nearly faced a breaking point early in the 1981-82 season. Then-third-year player Magic Johnson publicly demanded out of Los Angeles because of tensions with head coach Paul Westhead in November 1981. 
“I can’t play here anymore,” Johnson said. “I want to leave. I want to be traded.”
Fast-forward to 1982, and the Lakers put together 57 wins and eight straight playoff victories en route to the NBA Finals. There, they suffered just two losses to a squad that had the 10th-best playoff run ever (listed below). 
The Lakers failed to earn a spot in our top 10 because of their soft strength of schedule, average scoring margin and abridged playoff format.
1971 Milwaukee Bucks
W/L: 12-2 (.857)
ASM: 14.5
OPP: SFW (41-41), LAL (48-34), BAL (42-40)
OPP W/L%: .533
HOF: Jerry Lucas, Nate Thurmond, Wilt Chamberlain, Gail Goodrich, Gus Johnson, Earl Monroe, Wes Unseld
The Bucks, armed with greats Lew Alcindor (Kareem Abdul-Jabbar) and Oscar Robertson, obliterated opponents by an average scoring margin that surpassed every other contender on our list. All but three of their wins came by 12 points or more. 
Despite that, the Bucks also faced one of the softest schedules. That, plus only needing 12 wins, kept them from cracking the top 10.