"The correct question of course, is not whether or not St. Peter was entrusted with the whole Church, but what that entrustment allows St. Peter to do. That is the true difference between East and West up until now."
Well, there are and have been theological differences, some actually quite important at various levels. Most of those, however, have been looked at and not been determined to be insurmountable obstacles for one reason or another. Some, like the filioque, have had their explanations expressed anew to avoid problems while others, like the differences between Latin and Palamite theology on grace and the Holy Spirit are so arcane that perhaps 1 in 10,000 lay people even know what either of them are, let alone why they are important (and they are important).
Otherwise, your comment is pretty much spot on.
All of the differences such as Azymes and the filioque and such ultimately come back to whether the Pope has the power to do something (say, add a filioque to the Latin Creed) and enforce it upon the whole Church. So really primacy is the root of all the disagreements.