Originally Posted by The Joker
For another sequel it might have worked. But Harley had no place in TDK.
Agreed, Harley Quinn had no place in TDK and TDK just needed to focus on Batman and Joker for the time it did.
Maybe a sequel if Ledger was still alive, but even then, ehhh....there are better choices and TDKR was just fine in using Bane.