There have been many seasons of Survivor where the best player [for the public] didn't win. We see so little of what goes on around camp during the 40 days. Sugar was very popular during her 1st season, but she didn't get any votes because of how much she cried every day.
Also, the jury is very emotionally vested when they cast their votes. They don't have the time to stand back and look at everything objectively. Emotions and frustrations are still running high.
Jeff used to ask the jury [at the reunion show] if their votes would've been different if the final challenge winner had brought another player to the finals. In most cases, the response was 'yes'. Think Jenna M voting off Rob C during Amazon - the entire jury would've cast votes for Rob C if had been at the final vote. There have been many seasons where a 'coat tail' rider has won - Tina of Outback, Amber of All Stars, , Natalie from the prior season, etc.
However, I still contend that Sandra played the game to her strengths. She knew she wasn't going to win challenges; so, she wasn't going to worry about appearing weak. As she pointed out, it's part of her strategy. Physically weaker players are targeted when tribal immunity; however, the strong players are targeted more at the end. So, if a weaker player can survive through the merge without being irritating to the rest of the players, he/she has a good chance of going to final TC. I do feel she played a better game than Natalie who won last year. Natalie appeared to let Russell do everything to get her to the finals while she played nice with everyone. Sandra was playing - she tried to make moves but the Heroes were dumb. Her biggest move was getting Russell to vote off Coach, which ultimately kept her in the game.
I strongly feel that Russell deserved to win his 1st season because no one else was really playing the game - he ruled what happened. However, for H vs V, everyone was playing and I don't think Russell was the mastermind of every single move. Parvati pulled off some big moves independent of Russell and she won a lot more challenges than Russell and Sandra combined and she had a target on her back from day 1 (yet still made it to TC), which is why I felt she was the rightful winner this season. Russell and Parvati failed to make friends with the Heroes, who made up the majority of the jury. Between Russell's being a jerk to people in their faces and Sandra having made a couple of moves and the Heroes knowing that things would've been different if they had followed her lead and because she didn't offend people on the jury, Sandra won.