While it makes good drama, it sucks that basically everyone on the raft is now expendable. Michael and Walt have bonded, and their little arc sort of closed with Walt admitting to burning the first raft. Plus, Walt gave away Vincent in a big gesture. Jin apologizes to Sun, ending their separation (at least emotionally). Sawyer tells Jack about his encounter with Jack's dad, and he's finally been contributing on his own free will, in direct contrast to his early ways.
I can't see Walt dying though, since we know he's got powers. I could see him possibly disappearing though... ending up with the Others or something. It'd be weird if he came back to the survivors what with his giving away the dog. Plus, he's a kid.
Michael, Jin and Sawyer though, their current island arcs are resolved, more or less. It might not be looking good for someone.
