The problem with Angelina Jolie as Catwoman is that you don't then have "Catwoman" on screen, you have "Angelina Jolie in a Catwoman costume" onscreen.

One of the best things about Nolans' films has been his casting. Instead of putting obvious A-list superstars in the parts, he gives us up and coming actors (Bale, Eckhert, Ledger) or really talented character actors (Oldman), all of whom are skilled at vanishing into a role, as opposed to turning the role into a variation of their usual characters. (Note: Liam Nielson as Ras might be an exception to that rule, but even Neilsen is more of a character actor than not at this point).

Jolie would look good in the suit, and she's a decent actress and action star. However, having her as Catwoman seems more like the kind of casting that gave us Nicholson as the Joker, DeVito as Penguin and Arnold as Mr. Freeze, namely, the insertion of the "obvious superstar actor" into the part.