The odd thing about most of the Rogues Gallery is there's really not much more to work with for a REAL threatening opponent for Batman.
The Riddler isn't really MUCH of a villain. At least not one of a level that justifies him being the primary bad guy in the new Batman series. The same goes for the Penguin, who has more in common with the Falcones than Ra's and the Joker (and especially later on Batman largely tolerates in return for information). And I will say this again: CATWOMAN IS NOT A VILLAIN. She's usually on the wrong side of the law, yes, but she's much more accurately an anti-hero and wouldn't work as a primary villain.
