Frank Miller Update: Sin City 2 And 3, Spirit And The Dark Knight (Returns)

A new piece on Frank Miller in the LA Times reveals a few interesting things:

That The Spirit begins filming this year, two Sin City sequels are in the pipeline (I heard this was the case - two films being shot as though one, released a few months apart)... and the next Batman film might well not have the title we were expecting. Here's the piece of the article on that front:

...borrows its title from Miller's 1986 masterpiece, The Dark Knight Returns. "They finally got the title right," Miller said with a pretend sneer. "I was wondering when that would happen."

Of course, they may just have borrowed the first three words and not the fourth, but that's not the inference here, and it's starting to sound like they've gone the whole hog. Will that cause a problem?