I think that all of them have either an attitude, or trait, or personality that is unforgettable, and that is why out of all of the previous Survivors who responded for the All Stars, these ones were picked. This would also mean Richard's nakedness.
Rudy will be walking around cussing everyone who is different than him, Lex will be ferocious, Richard will be naked, Jenna will be pairing up with a female to take baths with, Big Tom will be watching their behinds, and Rupert will be winning immunity. Just a few examples of why they are all different, but playing the same game. That is the beauty of it. I cannot wait to see how they all come together.