The guy said "greatest ND quarterback ever by many objective measures," presumably statistics like yardage, touchdowns, TD-to-INT ratio, completion percentage, whatever else. Would you not say that the better description of someone ranking high (if not #1) in those categories would be "most prolific" as opposed to greatest?

and one of the things I like about this board is that we tend to ignore that sort of chatter.

if Book ends up being a great player for ND we'll all know it, see it, and recognize it. Tommy Rees might have had better stats than Joe Montana (for instance) but I don't know that many people would say that he was the greater of the two when it comes to playing qb at Notre Dame.