From the blog of artist Joe Quinones:

http://joequinones.blogspot.com/2016/03/batman-89.html

It would've been a mini-series that was to be set post Batman Returns, and introduce not only Billy Dee Williams as Two-Face, but also Burton-esque takes on Ivy, Harley Quinn, Robin (presumably the Marlon Wayans mechanic take Burton had planned but never did), and Batgirl. The blog unfortunately does not go into detail as to why it got rejected.