I don't think there is any rhyme or reason to Inquisitors, but this doesn't change the fact that England in my campaign has constantly been the one to get excommunicated.

In Repy to #4
The AI plays alot differently than a human player would. I still think England is predisposed to poor standings with the Pope and I'll bet if a human player never cared much for piety, not building churches or priests, that he would still be the first to get excommunicated even if several other nations were doing the same.