for fun, im gonna go devils advocate here..
we are used to the idea that cat woman is a contemporary of bruces, a peer.. young... social.. hot.. the one girl that bruce is repeatedly intrigued by..
so to bring that something new to the roll, make her more developed.. er ahem , older..
still social, but now not just a pretty face in the room, but an icon of high society.. someone who would have a developed taste for toys, not just someone who see the dollar signs but more of a collector than a pawn shop customer..
cher could fit that model... he is old, but for being old she still looks decent, and they do have movie makeup to work with.. not that i prefer her to pfeiffer but it could work.. they will have to do something about the acrobatic nature we are used to... but thats not a huge problem...
also, it occurs to me, (this goes against the 'realistic' nature of the current series) that she could be an introductory form.. nearly a cameo.. if cats have 9 lives, maybe she hands off the mantle of the cat woman to the next one... or, if you go by the Madam storyline cher could fit in nicely..
not that im in favor of any of that ... its just some ways that could be made to work..