For those who don't know, after successfully killing the former emperor Charles Di Britannia, Lelouch Vi Britannia took over the Britannian Empire, destroying the culture of Britannia, pulling a coup de-tat over the UFN(United Federation of Nations), and then successfully acquired the power of nuclear weapons(Damocles) over the entire world, declaring a true world dictatorship.
He then imprisoned those who went against the regime, and for a moment it looked like Lelouch, who once espoused the philosophies of freedom and the future, was going to lean towards Hitlerism. But then, something awe-inspiring happened.
He had his best friend, Suzaku play the part of Zero as he had a sword ran through him. Lelouch purposefully became the image of all that was evil incarnate, while building up zer0 as the messiah. This allowed the world to work towards the future and peace.
So I pose the question to everyone: Could the Zero Requiem work in real life? Could a leader become the symbolism of all that is evil, and lead to humanity rejecting said evils?
Well, the first two parts(becoming a symbol of evil) and a staged suicide would be easy to accomplish. The hard part is the aftermath, the people leaning towards the future.
IRL, we're just too opinionated(Religiously, etc) and somewhat bigoted in our own thoughts. Even if someone played the role of martyr, it wouldn't lead to anymore than at best "remembering him"(See:Martin Luther King Jr.)
So sadly, the Zero Requiem wouldn't work in my opinion.