There are negavtives and positives. Obviously not ideal for Sark to be calling his first game under this type of pressure, with no actual experience to lean on doing so at UA.
However, it could completely stifle Clemson's defensive preperation. Yes we will be calling many of the same plays with the same schemes and ideas, but the actual trends that good scouting will pick up on are a moot point. (Consistent play action passing on 1st downs, nearly automatic deep ball on sudden change middle of field situations, etc).
Its a shame this couldn't have been done before the last game. But there are also some positives associated... And clearly the move wouldn't have been made if the positives didn't outweigh the negatives in Saban's mind.