Nektarios,
Why doesnt a Orthodox Church send a Orthodox Bishop to take over the Roman Patriarchate? Not meaning the vatican and the popes, but establish an Orthodox Bishop of Rome? Since the RCC will never recognize their heresy and repent?
I think in times past the answer to this was primarily a political one. Up until relatively recent, a vast amount of Italy (including obviously the city of Rome) was part of the Papal States - basically under the same status as the now relatively small "Vatican City" is today (where the Pope is technically the monarch, as well as an ecclessiastic.) It simply would have been impossible for an Orthodox Bishop to be sent to Rome, assume the office of Pope, and view the other "bishop of Rome" as a heretical rival - and it's doubtful he would have had, save for the early period, much in the way of a flock either. Either way, the "Vaticanites" would have used force to throw out any Orthodox Bishop who visibly went to the city and tried to establish an episcopal throne. Even after the temporal fortunes of the Popes went into decline (with several confiscations of land from the Papal estates...Napolean, etc.), given the level of cooperation the Vatican had from the secular Italian state, the establishment of an Orthodox episcopal seat in Rome would have met with a lot of harassment if not outright prohibition.
As for why it is not done now (given Italy is now quite secularized, and the strange move of the Vatican after Vatican Council II to tear up all of their concordats with once "officially Catholic" states), the answer is again politics, but of a different sort - namely the ecumenical movement. I have a hard time believing the "official/canonical Orthodox" would involve themselves in establishing an episcopal see in Rome (let alone understand that Bishop to inherit the priveleges accorded by the Ecumenical Councils to the Bishop of Rome), while they're currently involved in affirming the legitimacy of it's heretical/schismatic occupents.
Seraphim