The biggest hole in the ransom sacrifice in my opinion is that there was no risk involved.
According to the Old Testament Jesus would be resurrected on the third day and therefore the whole exercise was a foregone conclusion. So what did it prove? It only showed that an individual would do what is needed if the reward was great enough. Compared to the story of Job, the ransom seems hollow. If Jesus had died and was not resurrected, now that would have been a real sacrifice.