Why? Joker is a character that can be interpreted in many ways. The joker has been chunky and oldish in the joel schumacher portrations, in comic books he's been super skinny, he's been some weird zombie like gorilla guy, he's been a loon that cut his face off, he's been one that cuts his mouth with razorblades. it seems in this universe he's psychopatic trash that really enjoys inflicting pain on others and has a weird sense of humor ( look at his tattoo's ). i think you can simply scratch the idea of robin as the joker away simply because of the rioting in what seems to be arkham asylum and joker is gonna torture harley quinn. Further more, why would robin be in arkham? Robin losing it, yes. Actually becoming the guy who assaulted him? i don't think so. It would be too many similar psyche breakdowns for the characters in 1 universe. Harley quinn is going to flip/crack due to the joker traumatizing her and turning her from dr. Quinn (not the medicine woman) to crazy Harley. Having the same happened to robin before? Robin for some reason breaking mentally and turning into the joker? two more or less similar theories? no way. The Red hood is imho the only reasonable and believable story for a goodguy-turn bad in a batman universe. I don't see why Joker can't be buff. Why wouldn't he work out in arkham? a buff joker is even more threatening rather then a skinny pale weak psycho. If he's gonna have to stand his ground against harley, he can't be weaker then her and not by just a mere margin. just look at how athletic she is.