That's a crazy first post.
I think, during the semifinals of the French Open against Henin-Hardenne in 2003, that had Justine not raised her hand, Serena would have won. But, if she wasn't mentally strong enough to handle that incident, who's to say she would have handled it if they went deep into a third set?
At the Wimbledon final against Sharapova, she played like crap, but Maria played incredibly. She deserved it to the top degree. Serena had to be ready in the biggest tournament of her career and she wasn't. Wimbledon - you have to be ready for that tournament, and she simply wasn't good enough that day.
The 2004 US Open quarterfinals is the dumbest yet, though. Serena fully recovered after that terrible line call...well, the line call was at 1-0 or something and she would have gone up 2-0, right? Anyways, she ended up going down 5-4 anyways. But, the 5-4 game was insane. More line calls. But, we don't know if she would have dusted Davenport, Kuznetsova, or Dementieva anyways.
I think the real Slams Serena should have won were in other times. In 2003 and 2004, the US Open and Australian Opens, respectively...On hardcourts, Kim and Justine were simply not competitive and they were the dominating forces during those Grand Slams. I would say #8 and #9 would have come there. Also, maybe the 2002 Australian Open.