But the restored army and bureaucracy wouldn’t be the legitimate successors of the old army and bureaucracy. The Church was truly the only remnant of the Western half of the Roman Empire.
Well then, I guess Europe in Jacob Harrisonsville is doomed to eternal anarchy, now isn't it? As I said, under Roman law (you know, that thing you're citing as the reason why the emperor's descendants are not and can never be the rightful heirs), the Church never had the authority to redraw the borders. If you think it has the right to change the rules for any reason, then you don't get to arbitrarily say that all future changes are wrong because reasons.
Pick a standard, any standard. But remember, you only get one.