Onto the next bunch of castaways ...
Andrea - Game changer or not? About the only game changing she did in her first two seasons was to perfect the art of being blindsided! She is smart to be leery of Tony. But I think just about everyone is going to be leery of Tony. She wants to align with Cirie. However, to me, Cirie is one of those people others need to be leery about. No one should want to go to the end with Cirie. I don't think Andrea is a particularly strong member in this cast made of so many strong players.
JT- Game changer or not? Oh, I'd go game changer for JT. The first season that he played (and won it all), he was a triple threat as far as this competitive reality show goes -- physical, mental and social. He made some mistakes in his second season which are still obviously biting him in the butt. Like Andrea, he's leery of Tony. (Everybody is!) I think he's wisely sizing up Ozzy and Malcolm to not only align with, but roughly use as shields. If he could get to the end with them, his social game rules. If they fall along the way, it's them not him.
Malcolm - Game changer or not? Well, for someone who hasn't won the show twice already, I think he kind of is a game changer. He's entertaining to watch on the show. But he plays rather unfettered -- he doesn't seem to think ahead. It'a not quite like chess, but you do have to be very observant and think a few moves ahead in order to stay in. Like the others in this post, he's leery of Tony. (Poor Tony.) He's also leery of Cirie and Sandra -- a smart leery on his part. He does have a strong physical game. I don't think his social game is as fantastic as he thinks it is, but we'll see ...
Aubry - Gsme changer or not? I think she is a bit of a game changer. At the beginning of her last season, I almost dismissed her and thought she'd be gone before the merge. She's not someone you'd really expect to go far. I don't know if her proposed read of people is quite up to the level of Tony's skillz, but hey ... she just might do it. I'd say she's an unlikely winner, yet I'm thinking she just might have some there there.