I think that people will never be satisfied with any one model or a system - no matter how good. It's in their nature.

There was an excellent scene in Spartacus: War of the Damned final episode that pretty much sums up the concept of "fairness":

"Crassus and Spartacus leave the others for a face to face.
In conversation, Spartacus lets slip that a female slave killed Tiberius.
The two men compare personal losses; Crassus has lost a son, Spartacus, a wife.
“There is no justice, not in this world,” Spartacus says.
“At last,” Crassus responds. “A thing we agree upon.”
The two men clasp arms.