Isn't an upvote something you feel should be on the front page? What's the different between the way upvotes count and the way vouches will count? Does one weigh heavier? Was it not in the cards to make upvotes "vouch" for a post?
I'm not sure I understand all those questions, but years of experience have shown that votes and flags are radically different things, and vouches are very much on the flag side of that distinction.