It sounds like you never heard any of the arguments against your position, ever. There is no reason to why Russia should be hostile to the papal states because the pope tries to form the nation of god. AE has artificial barriers that made no sense from any point of logic. Nations far from your own, with no conflict of interest that suddenly hated you even after a century of royal marriage and alliances. Strategic alliances was also almost impossible, Liberate Serbia as Austria and suddenly serbia hates you because you fight someone else in a completely different region resulting in the Ottomans annexing Serbia once again...thats not logic thats bad programming.
You must have played a different game, or I'm misunderstanding. When expanding as the Papal State, the AE increase in Russia would be negligible. If you have an alliance, the AE increase will also be MUCH lower, so allies "suddenly hating you" is simply not true, especially not if they are "far from your own nation". Additonally, the AE increase depends on the attitude they have towards you, which makes perfect sense. If they really like you, AE increase is low, if they are your rivals or you already outraged them with conquest, further aggression will be punished harder. All this is completely logical for me, and I haven't experienced what you are describing (in 1.3).
