A lot of pressure on Venus
IMO, Venus has all the pressure in the final. People (including their father) have been saying since the beginning that Serena will be better then Venus.
Serena has just surplanted Venus as the no.1 player. She has also beaten her the 2 times they played this year including the French Open final. If Serena beats Venus again, then I feel that it will be hard on Venus to accept it. Also if Serena wins, she would have won 3 different slams as opposed to 2. I just think that Venus has a lot of pressure because if she loses again, it will show the world that Venus is the past and that Serena is the new Queen.