what happens to motherless brooklyn?

It's still has a place on imdb- it just doesn't have it now on Edward Norton's credits.

http://www.imdb.com/title/tt0385887/

I would probably say it would be better if Nortion walked away from this project. When films get struggled to be made they usually get damaged in the creative process and end up mediocre whether commercially or critically. There are always exceptions to the rules (One flew over the Cuckoo's Nest), but just speaking generally.