Several early Christians believed in universal reconciliation. Among them included St. Maximos the Confessor, and the Church father who ultimately wrote the Nicene Creed. There has only been one rather narrow form of universalism condemned and that was purported be Origen. He taught rather dogmatically that even Satan and demons would ultimately be reconciled. But, honestly even this was not the promotion of his anathematization. Moreover, he taught a disdain for the Old Testament Canon which ultimately brought him to resemble the Gnostics.
Otherwise, even as the Orthodox faith was being qualified, universalism was an acceptable view, provided it was not taught dogmatically (thereby encouraging people to sin) and that it maintained the main essential articles of faith. The main reason for this is because even the most hellish proponent must recognize that we simply do not know what is at the end of the tunnel. We only have the inspiration through scripture which is not altogether definitive on the subject, i.e. what is the punishment? Some have purported that hell has different "levels" and have gone as far as to say that the less severe levels, commonly called Limbo, for moral pagans and unbaptized infants, is a perfectly comfortable place albeit separated from God.
Mostly what people object to is the notion that temporal sins, however heinous, are still just that, temporal. So how is it just punishment to endure eternal torture? That is why I believe that hell is not so much "punishment" for one's sins, it is a consequence of it. How well someone has aligned their will with God's determines how painful or joyous His love for them will be.
