I was raised in a pretty Catholic family (no I'm not Italian, but my great aunt is...). Anyway from my knowledge of church history, I've learned we've had amazing popes and poopy popes. I think that being a vicar of Christ is earned, not immediately known. Normally if they come off as a nice cool dude people will like them and he's a vicar, but say you were a loon pope then people wouldn't say they were a vicar.
In short I believe the pope has to EARN the right to be called a vicar of Christ.
PS. Your a Protestant and your asking we Catholics to respond. That's kinda funny because I asked a Lutheran Spanish Teacher at my school if the pope rumor was true.