I don't really like that Vivi ending. The implication that Vivi is dead is to central to his character, and the overall feeling of the Blackmages. They are faced with the fact that they have a limited time on this world to live, and have time and time again tried to mask their own mortality by covering up the word death with stopped moving.

To simply prolong their life with a machine is nothing more then them running away from the truth, and defeats a lot of the symbolic value held by the blackmages, if that makes any sense.

But yes, a scene a bit more descriptive on the Kuja/Zidane interaction at the end would be nice.