Right, it's left very open-ended as to what happens to the Joker. The last we see of him he's dangling off the side of a building with a SWAT team closing in on him. But, we don't see him die and we don't even see him actually being arrested at the end. So, anything is still possible with him... especially since throughout the film we've seen him escape from very improbable situations.
That's my general question about Batman villains... I think they all are capable of returning repeatedly somehow.
I hope with all my heart that they do not bring the joker back.He is for me now,definitively and irrevocably linked to Heath. They need to ressurect one of the other villains.In fact I have found the whole TDK so hard, that I almost hope the Imaginarium does not get released.Wounds which may be starting to heal by 2009 ,will just reopen.Even the thought of the Oscars, fills me with dread.
The worst thing about TDK was all the premiers with a great big gap, where Heath should have been,looking embarrassed by all the praise, self deprecating as always, and just one big fidgit.Who would have thought one man could leave such a gaping chasm.