MaulFan, we can't assume anything here only speculate (myself included).
I mean, just look at this announcement. I know, like you, I had SERIOUS doubts they'd ever make Batman Returns figures and yet, look where we are. There was this possibility, sure, but today?
These films lend themselves to figures. How could Hot Toys pass up on someone like the Joker when all they have to do is give him a few variant clothes and paint his face flesh? If this DX Joker is a hit and sells well I'd be more inclined to think there will be more. Who knows though.