The gods were re-invented to show their human side (e.g. Heracles) which included their being re-casted as seekers of justice. This validated the sense of justice and morality emerging in the new Greek society, and made the gods the standard for right and wrong.
Lastly, cults appeared as an emotional safety valve. Orphism, mystics, seers, and mysteries helped to put the unknown answers to life in a box. Three major cults emerged – those of Dionysus, Apollo, and Heracles, with the former dominant. Cult worship evolved as a way to purge away fears and reassure the individual he could survive.
We see these significant adaptations in Greek religion and wonder about them. Surely religion was serving as a emotional guide, allowing man to think in new ways. But man has always adapted his religion to his situation. Just look at the MTV churches we have today.