This comes of reading Schaff and New Advent side by side, as well as developing a them from some other threads.
In a nutshell, what bothers many non-Catholic Christians about the pope is that he is so freaking arrogant. He oversteps his bounds. He is a power hungry maniac. Egotistical. Unilaterally deciding things. Without any sort of earthly check.
Given that the powers of the pope have developing over a long time, and have passed from councilar decision making to the form we see today, what, exactly, kind of a Catholic pope would be acceptable to Protestants and Orthodox? A primacy of honor but not of administration? Is there a REASONABLE change the Catholic Church would make that would eliminate this matter as an issue that keeps you from being Catholic?
I have not, by the way, looked into all the occaisions on which Popes have been accused of arrogant overextension of power. I am not sure what an arrogant overextension of power is on the part of a pope, because as far as I can tell, Catholics say it cannot happen in the arenas of faith and morals. On those occaisions I have looked into, I have not found it mandatory to read the incident as an indication of papal arrogance. Perhaps there are some, but alternative explanations seem to be available, if one drops the filter of looking through history at the pope as the Anti-Christ.
So, here is a thread in which this Protestant is taking the position that the Pope is not arrogant. It might be interesting if a Catholic endeavors to prove me wrong on that point.