I am new to this board too so I want to thank you for your constant updates. Have to disagree with your assessment of Sharon though. She did some pretty stupid things...made out with almost everyone in the hot tub...made out with Matt quite a bit as well. She didn't do as much as the other people, but she isn't exactly a saint either.
I feel that Adam getting her out of there was the perfect move. She is way stronger than Sheila.
The two most devastating moves, in my opinion, were the following:
1) James keeping Ryan over Matt when he had the HOH and the vote was tied. Had he kept Matt, he would have had an alliance with Matt, Natalie, Chelsea, Joshua, Sharon, and himself. Then Adam and Sheila would have been the next ones to fall and the final three would have included 3 from his group.
2) Natalie NOT taking the deal from James, then GIVING James HOH. Had she kept HOH, she could have put Ryan and Adam up, and gotten rid of one of them, and also had an alliance with James, Chelsea, Sharon, Josh, etc. However, she probably would have gotten on their nerves, like she did Ryan and Adam, and they would have voted her out anyway.
Those two decisions were what shaped the final 5 players in the game.