5. The Joker
Many of the Joker's problems can be explained by the fact that the character is criminally overused. In order to be effective, a villain should be used sparingly. In recent years, it's been hard for classic villains like the Joker, Lex Luthor, Dr. Doom and Darkseid to maintain their luster since they've been demoted from threats to - for all intents and purposes - supporting characters. How can you possibly get excited about Lex Luthor if he's featured in fifteen comics every week? Familiarity breeds contempt, and nowhere is this more true than for villains, for whom familiarity means simple boredom.
The Joker is Batman's archnemesis, for better for worse. Batman's rogues' gallery is filled with dark reflections of the hero, funhouse versions of the Dark Knight that accentuate different facets of the Caped Crusader's personality. The Joker, though, works on more than just one or two surface levels, and represents something far more frightening than most of Batman's foes: he's something deeply sinister wrapped in a profoundly anodyne exterior, he's evil dressed as the least threatening guise possible. The Joker's power comes from this juxtaposition. He's a clown - not even a particularly impressive clown, just a schmoe with green hair and white greasepaint in a comical purple tuxedo. Except . . . it's not greasepaint. Somehow, that's his actual skin, chalk white and gleaming in the moonlight. And he's laughing, really laughing - not some sinister, throaty chuckle, like a cackling movie villain, but real, genuine hysterical laughter. He's really enjoying himself, he thinks it's all quite hilarious. Only, you might not like the punchline. You might not "get" his sense of humor.
The best live-action Joker is still Cesar Romero. Why, you ask? That's absurd. Heath Ledger's performance is undoubtedly "better," if by that you mean he is convincingly menacing and sinister and monstrous. But you know what? The Joker in The Dark Knight doesn't really seem like the Joker I know and loathe. He's a filthy, muttering monster. Cesar Romero? Dude is just batshit crazy, and obviously having the time of his life. That's the Joker you can see turning a considerable talent for chemistry to the sole purpose of developing a gas that makes people laugh themselves to death. That's the Joker willing to build a giant automobile with his face on it just because it'll piss Batman off. That's even the Joker who'd walk into the United Nations building as the newly-appointed ambassador of Iran with the sole intention of killing every last assembled head of state, just to see if he can actually get away with it and piss Superman off in the bargain.
The Joker is Batman's #1, but he needs some time off to get his mojo back. We're so used to a Joker with preposterous, credibility-demolishing body counts, it's easy to overlook just how freaky the idea of a grinning clown with homicidal urges might actually be.
My suggestion? Kill the Joker. Dead serious here: make a big deal of it, huge event - "The Death of the Joker." Get it on the evening news, even. Make it as solid and ironclad a death as conceivable, and then keep him dead. Obviously no one is stupid enough to imagine that the Joker will be dead forever, so they'll be looking for him to come back sooner rather than later. But keep him cold for a while, and what's more keep him out of comics altogether, as much as you can - no prestige format books, no Legends of the Dark Knight, nothing. And then, after a few years of this - maybe four or five, if you can possibly keep it up that long, then you bring him back. I promise you, if you could keep the Joker dead for a significant enough amount of time, his comeback would be a big fucking deal. It might actually be interesting, which is something Batman's archnemesis hasn't been in a long, long time.
There is a very simple question at the heart of Anarky's character which defines his dynamic with Batman: how is it possible that the avatar of law and order in Gotham City is a violent, extra-legal vigilante? The state - by definition the monopoly of force, whose most basic justification for existence is the preservation of public safety and civil order - is unable to control the forces of chaos within itself, and must depend on the goodwill of an unlicensed super-hero - a free agent existing in direct opposition to the state's putative monopoly of force - in order to maintain itself. What justification can the state offer for its own existence if it can't fulfill its most basic covenant? The existence of Batman, and his continued tacitly-approved operation, shreds the social contract. Without Hobbes and Rousseau, we're left with Marx and Bakunin. Without even the pretense of direct democracy, government devolves into republicanism, and from republicanism it lowers itself to oligarchy, and from oligarchy the nature of the state as the mechanism of naked, unrestrained power stands revealed.
That's the idea, at least. Admittedly, most of the charm behind Anarky lies less in the execution than the potential. Historically, he's been strongly associated with his creator, Alan Grant, who conceived him as a potent challenge to Batman on the grounds of challenging Batman's legitimacy as a representative of the state's worst authoritarian tendencies, unfettered by legalisms and loosed upon the city's permanent economic (supposedly criminal) underclass. There have been precious few Anarky stories, and some of these haven't been that great, but in terms of sheer potential Anarky reveals one intriguing idea after another. The idea of a character who commits crime not out of insanity or avarice but a genuine, principled opposition to Batman and the socio-economic forces which he (wittingly or no) represents is fascinating. In fact, it's not hard to see in Anarky a variation of Frank Miller's conception of Batman in the first 2/3 of The Dark Knight Strikes Back - a principled terrorist bent on destroying authoritarianism through individual initiative.
The best part about Anarky is that, regardless of where you sit on the political spectrum, he nevertheless represents a coherent philosophical challenge to the Powers That Be who, based simply on the ingenuity with which he challenges Batman, cannot be easily dismissed. Add to this the fact that the character is, ultimately, an immature and callow teenager, untested by experience but motivated by nothing so much as an unimpeachable sense of self-righteousness - sort of an anti-Robin. In Anarky you have the potential for one of Batman's greatest challenges - not just a physical or mental or even spiritual challenge, but a challenge to his ideology.
The Riddler is one of, if not the most high-profile casualties of DC's post-Crisis, post-Dark Knight tonal shift. Neil Gaiman did a great Riddler story in a 1989 Secret Origins special that explicitly defined the character's problems in the superhero climate of the late 80s and beyond: he was a gimmick villain whose greatest wish was to pull off a perfect score and have fun doing it. He wasn't a killer, he certainly wasn't a sociopath, he liked goofy themed henchmen, outsized deathtraps and played the game by a generally outdated set of "gentlemen's rules." This was a great story (and is probably the only time you'll ever see Gaiman, Bernie Mireault, Matt Wagner and Joe Matt between two covers, let alone working on the same story), but it was so memorable that it stuck the Riddler in time as an anachronistic bumbler. Sure enough, the next couple decades were not kind: he was egregiously suckered by Bane in the lead-up to Knightfall, abandoned by his own traitorous henchwomen soon afterwards, repeatedly humiliated (both in the context of the comics themselves and by creators seemingly too embarrassed by him to do anything interesting), and generally shat upon mercilessly. Let's not even mention Hush, which still doesn't make a lick of sense.
But why does it have to be this way? Think about it: the most popular (non-childrens) books in the world are mysteries - be they whodunnits or crime thrillers or conspiracy stories. Seeing that Batman is - or at least was once - the "World's Greatest Detective," it makes sense that he would have an arch-nemesis devoted exclusively to the creation of mysteries. Nowadays, the most detecting Batman ever does is call in a question for Oracle or one of his other assistants. It doesn't help that few Batman writers seem able to write a genuine mystery to save their lives. But how about a Batman villain who isn't a psycho, who isn't necessarily even a violent criminal - just, say, a man with a mania - some might even say an obsession - for making things fit, for putting together all the pieces to puzzles that other people don't even perceive. And of course, when he figures things out, he isn't content just to enjoy his own private knowledge, he has to share - or at least, he has to leave the clues there for anyone with the brains necessary to follow his formidable train of thought.
Batman has psychotic killers, megalomaniacal world-beaters, tragic monsters and even alien despots in his rogues' gallery, but the one thing he doesn't really have is a purely cerebral foe, someone who can match the Detective wit-for-wit, someone whose most basic metier is designing the perfect crimes. The Riddler has been a joke for over twenty years, but he doesn't have to be. What Batman needs is his very own Professor Moriarty. Thankfully, he already has one, sitting in the corner and slightly dusty from disuse, but a very sturdy concept nonetheless.