I really think a lot has to do with the social game that the different people played as well. I wouldn't say Sophie got carried through entirely, but a lot of the people that you mentioned such as Denise, Sophie, Tina and Sandra played a great social game. Monica hardly had any social game (one juror even mentioned he didn't know who she is and wanted her to bear it all and showed all her emotions, to which she did and I thought it was awesome.. but isn't it all too late)?
Throughout the whole game, all we got to see was Monica being panic, Monica being run down by people simply because of the way she reacted to people as well. She played both sides, but never once was she really interested in playing with the others except just Tyson and Gervase. Monica, IMHO, played a horrible social game. And that's why I thought without a social game, perhaps if she had made those crucial (yet useless moves, because the ending would have been the same probably), maybe it would have granted her a stronger case to win.
For example, Denise dealt with the jury questions horribly and didn't really play a strong social game, but she still won because she had the strongest case to win. She was on the total losing tribe and attended EVERY SINGLE tribal council. She would be the last person I say who got carried through actually. She had to fight for her life every single tribal council.. back to Monica, if she had actually used the case of her being in contact with various alliances, where she could play whatever she wanted but instead, was pulled down by a last minute killer comment by Tyson that she thought Monica should win because she always pretended she was at the bottom of the totem pole but was actually in a strong alliance with Tyson and Gervase, so that she can be the double agent and pass useful info to the both of them. I thought had Monica used that as a case for her to win as well, maybe she could have gathered one or two more votes, considering this isn't a bitter jury. It's always hard to play the double agent and this is so much a better argument than her saying that she's always on the outside when in fact, she's not and always tight with Tyson and Gervase.
Just a lot of perspective going on for Monica's game which I felt was lacking the social factor. But I'm glad she did came in second and not third, because Gervase was honestly useless.