I dont think they would go withy the Red Hood origin, since they're trying to make these films seem more realistic.
Batman has his costume for armour, and for provoking fear.
Scarecrow uses his for inducing terror.
There is no practical reason for a criminal to run around with a red hood on his face, and if he was the red hood, it wouldnt make sense for him to leave joker cards at the scene of crimes.
I think he'll already be the joker, because 1- everyone already knows the origin, and nobody wants to see half an hour of what they saw in Buton's first movie, they want the new movies to be different.
2- It will make this joker seem more powerful. The joker from the original movie was just a guy, you knew his name.
The joker in the comics has no name, he is only the joker, and because there is no other identity attatched to him, he has nothing holding him back. In this movie, I hope the joker will be to Batman, what Batman is to other criminals- he'll be a mystery, a symbol, and thats how it should be. Otherwise, the joker is just another psycho.