10 Problems With The Joker Nobody Wants To Admit
6. He Essentially Has Super Powers
The reason that the lack of an origin story is a problem for The Joker is that it places him in rather a different position than the majority of Batman's rogues gallery. Whilst he does have some larger-than-life adversaries like Ra's al Ghul, Killer Croc, Clayface and Orca (shudder), the whole point of the character is that the majority of the villains he faces aren't any more powerful or magical than he is.
Scarecrow has that funky gas, and The Penguin has a weird face, but they're still pretty much just human beings. Which is fair, too, since Batman is just a man a highly trained man with a lot of resources, but still just a man. The one superhero in the DC Universe who doesn't actually have superpowers.
And yet his greatest enemy clearly does.
Now, in-universe The Joker is simply just a man, too. Albeit a totally insane one who too has a lot of resources (and a seemingly endless supply of henchman ready to throw their lives away for him at a moment's notice). But he's clearly in possession of some sort of superpowers, or else he wouldn't be able to get away with half of the schemes he's managed to pull of over the years.
No regular person could have the amount of foresight to successfully initiate all of his evil schemes, the ability to be in multiple places at once or else so quickly, the nigh-invulnerability that's kept him alive all this time. The Joker's no man.
You probably knew that though.