When I asked that question, I was told that it was because he is the most popular Saint in the Orthodox Church who suffered much for the Church and is a great intercessor for the Church. He stood up against Arius at the Council and for his actions was censured by the council only to be vindicated by Our Lord and the Blessed Theotokos before the whole Councsil. he is a powerful wonderworker and patrol of almost every major group in the Church, Children, seafarers, Russia, Greece,bankers, the abused , the abandoned, the prisoner etc. St. George is the next most popular Saint. These two Saints also are noted to have the most Churches in Orthodoxy named after them than other Saints due to their powerful intercessions.