I heard they were trying to do a Winners vs Jury vs Early Boots type of season, but then had last-minute changes and had to figure something else out. Sierra and Hali are questionable, but everyone else I can see why they brought back. But at the time of Micronesia, Parvati was a dud, too, but showed what she can really do. Kelley Wentworth was a dud in her first season as well, then came back with a strong second showing. My guess is these two are players the casting department think didn't have a chance to shine the first time around.
As for the rest, I'm so over the Ozzy hype. He was fun in Cook Islands, but quickly became someone I dislike in Micronesia. He plays the victim. He is arrogant because of his physical dominance, but really lacks in the social and strategic components. I'm excited for Aubry again. Cirie at first I was not looking forward to, but she is really one of the best to ever play. She was a near two-time winner had she gone to the end in Panama, and had it been a final 3 in Micronesia. I've been a big critic of Sandra's game, but I also acknowledge her strategy is to play an under-the-radar game. I'm a fan of Malcolm, and I think he could be a favorite to win. Tony will be interesting to watch on a second season, but I'd imagine he'll be a quick target. Andrea is also a favorite of mine, and I could see her winning. Everyone else is just kind of there.
And that became a lot more analysis than I intended.