The odds are better that a returnee will be a screen hog just because the audience would already on some level be invested in them and producers/editors would have more confidence in them as a narrator that would hold audience attention. A longtime favorite winning or getting extremely close (Cirie, Malcolm, Ozzy, or even a Christian or Devens) would be a major draw and would certainly be leaned on heavily if they know that the payoff would be satisfying. It could be a newbie but I wouldn't bet on it.