Batman 3: The Curse Of The Man-Bat
Why? It'd be fun to see Batman fighting what is effectively a mutated version of himself, especially if it turned out that reversing the human/animal sides of their personas also meant reversing their respective skills and weaknesses to some extent.
Then again, it'd also be massively unrealistic, and not very Nolan.
Showdown Scene: Sonar would definitely play a role here: Dr Kirk Langstrom became Man-Bat while trying to create human sonar, so some kind of electro-jamming might work well against him in a boss fight.
We invisage his steering systems going haywire, and Man-Bat skewering himself on Gotham's pointiest architectural feature.
Batman 3: The Plastic Menace
Villains: Professor Pyg.
Why? He's one of the creepiest villains Batman has ever faced in the comic books and graphic novels - a pig-masked extreme plastic surgeon, hell-bent on creating his semi-human army of aesthetically immaculate brain-drilled Dollatrons.
Which is essentially something Jeffrey Dahmer tried with a few of his victims, so...y'know, quite scary.
Showdown Scene: Like a less campy version of the Austin Powers 'fembot' scene, Batman finds himself surrounded by a ghoulish gang of carved-up, gender-reassigned humanoids.
Bats has to kick lots and lots of automatarse before carting Prof Pyg back to Arkham. Where he clearly belongs, the whackjob.
Batman 3: Gotham's Riddle
Villain: The Riddler.
Why? Because since Gary Oldman hinted at the likelihood of The Riddler being a key third film villain in some of his PR work for Dark Knight, we haven't been able to shake the idea completely.
It'd have to be a very different Riddler to Jim Carrey's cackling panto villain in Forever , mind.
Showdown Scene: A Saw -style puzzle from which Batman looks unlikely to emerge unscathed - not just some ludicrous Heath Robinson Death-o-Matic™, but an existential paradox in which the keys to his escape are buried under shocking revelations.
The Riddler needn't actually be present any more by this stage; in fact, it'd give things a bittersweet kick if he'd already been defeated or fled Gotham.
Batman 3: The Puppet Master
Villain: The Ventriloquist.
Why? Men with smaller wooden men on their knees are terrifying.
Especially when the smaller wooden man dresses as a 1920s mobster, is called 'Scarface', and commits sickening crimes on behalf of a larger, non-wooden man buried elbow-deep in his rear passage.
Sounds silly, but the Ventriloquist doesn't come from Batman's camp, sixties-era, but the gritty post-Burton '90s incarnation.
Showdown Scene: It would be cool if the ventriloquism theme turned out to be a wider metaphor - Batman discovers his villain is effectively just a puppet himself, being manipulated by a far shadier and more powerful string-puller...
Batman 3: Moth Man Returns
Villain: Killer Moth.
Why? Well, we've already considered the horror of having Killer Croc as a central bad 'un - we might as well go the whole nine yards, and tarry for a moment on the chilling notion of featuring Croc's even shitter zoological chum.
Also, he wore stripey Spandex and a rubbish orange cape, which we'd love to see Nolan attempting to 'reimagine'.
Showdown Scene: Something stupid involving an Icarus-style enfrazzlement on the filaments of a massive lightbulb? Crushed into a weird and inexplicable dust beneath the rolled-up newspaper of Commissioner Gordon's mighty SWAT units?
Oh God, who cares - this was a terrible call.
Batman 3: Penguin's Progress
Villain: The Penguin.
Why? Because it'd be a tricky scripting challenge for the brothers Nolan: can they feature The Penguin without making him look like a cartoonish freak, as he's usually portrayed?
It should be doable - less of the "Waugh! Waugh!" bobbins, more of the oily playboyisms and ricin-tipped umbrella terrorism - but they'd be on thin ice, and we'd be fascinated.
Showdown Scene: Batman chasing the former Oswald Chesterfield Cobblepot (take that , Dickens) through a crowded subway station, a toxic brolly taking out innocent pedestrians left right and centre. Does our hero stop to deliver the antidote if it means losing his villainous quarry...?
Batman 3: The Dynamic Duel
Why? Because we don't really want to see The Boy Blunder flapping into this franchise at all, thank you very much. If he does, we'd rather the Nolans ditch the Dynamic Duo mythos and introduce him as an enemy - at least that'd give the future partnership fewer worryingly inappropriate undertones.
Showdown Scene: Some sort of plea bargain might explain things in less douchey terms than we're used to.
We don't see this as a get-out clause offered by Batman himself, though - it'd be better if he was forced to side with our hero as a double agent for a corrupt cop. Cue interview room beatings agogo. Huzzah!
Batman 3: Inglorious Batman
Why? Because superheroes always end up fighting Hitler at some point or other. Usually when the writers run out of ideas; just after cancellation of a faltering spin-off series featuring baffling and wildly unpopular villains like The Carpet Salesman, for example.
Showdown Scene: Nolan is smart enough to make this very much an allegorical Hitler figure; a racist, homophibic reject who believes in an all stick, no carrot approach to righting Gotham's sociological wrongs.
The showdown should happen at this twat's own mini-Nuremberg: a press conference crashed rather bloodily by Batman, whose intentions backfire - Gotham erupts into fascist riots, creating endless rogue factions as antagonists for Batman 4 .