EL James, Malala Yousafza, Barack Obama (If it was only for America), Mario Draghi. These are the only candidates I'd actually vote for, and Malala if I had to pick one. Draghi is second, Obama third, James fourth.
You have to actually done something, that affected everyone. Zuckerburg and The Protester were great picks. Obama did a lot during his term that drastically changed America, but much doesn't affect the world. Actors, singers, and athletes winning it is just ridiculous. EL James is a weird exception because I actually believe her books are changing the way we look at certain things.
I think Mars is a waste of time, and isn't really changing the world. Just my opinion. Obama will probably win it, as Reagan and Bush did after winning a second term.