Now, it is my understanding, that the Pope is considered a heretic. But, before the Great-Schism, why was the Pope allowed the best seat at an Ecumenical Council and was recognized as the first among equals?
If the Pope was given the best seat in the house why was he never in it?
That is because the East took care of things when it mattered.
Probably because the Role of The Patriarch of the West or Rome developed differently than the role of the other historic Patriarchates. The role as a Political Ruler was a role played by the Patriarch of the West only prior to the schizism. When one is ruling a political entity such as the papal estates, one is also in danger of revolt and replacement while attending to business out of the secular kingdom---this is the reality of why a Pope did not attend the Ecumenical Councils but only sent legates and then confirmed the Councils. I am not sure that the other patriarchates always had patriarchs attending as well but know that it was seen as a council that all bishops who could attend thus making it ecumenical or a church wide council.