I was thinking about Scarecrow the other day and what he would be like on a new show. The fear-toxin is the kinda thing they do on "Fringe" all the time. They could have an episode start at a rave or something where some drugs are getting passed around. Turns out the drugs are laced with fear juice, sh** goes crazy, etc. Get a good director behind it, throw in a few simple but icky SFX and you'd have a hell of a teaser.
Also, Crane could appear on several early episodes well before he becomes Scarecrow.
And a few other things I'd love to see on a Bat-show:
-More mystery and detective work. If he can't bust out the Batwing every other episode, they can make up for it by throwing plenty of cool, twist-filled mysteries Batman's way.
-Catwoman as a major character. Selina should be the Damon Salvatore of the series, extremely charismatic, getting most of the best lines, not truly a villain but too unpredictable to be a hero. And watching the secret identity shenanigans between her and Bruce/Batman would be like watching two master spies go at it.
-Harvey Dent's entire arc, both before he becomes Two-Face and after. Especially after, because he would come back as the show's new main overarching villain. I'd really love to see Two-Face get put on trial and he of course defends himself (like in Dark Victory).
-Riddler. The great TAS reinvention only got 3 episodes as the main villain, and an hour-long series would allow for the more complicated stories that the TAS writers just couldn't pull off. It'd be amazing too see a similar version achieve that potential.
-Clayface. Of course it wouldn't be the TAS Clayface, which was already a mishmash of several different iterations of the character. A live-action show would simply apply a different mishmash that makes sense for a TV budget. There's a lot you could do with a shapeshifter; it could make for a great mystery that would keep everyone guessing, even fans familiar with the character.
-It's time to bring back Vicki Vale. The idea of a reporter trying to get the scoop on the Dark Knight is good meat for a prime time series.