Sure DITF had Shelia Haywood and many fans still debate if she was actually his real mom. But there seemed to be another development I haven't seen anyone really talking about.
According to Collins there were plans do do more with his storyline involving Two-face and Willis Todd.
"I had a whole storyline developed that was later ignored that had to do with Jason's father and Two-Face. I frankly don't remember exactly where I was headed, just that the book dropped my concept and went in a direction that ultimately led to the fans voting Jason's death."
When I first read the interview I assumed he meant that Jason would try to find out what his dad did that lead to his death. Something along those lines that would have him dealing with it. But when Jason looks at the bat computer he discovers this:
Willis Todd is PRESUMED dead which means his body was never found. Sure this was ignored in DITF where we get a panel saying he was murdered but we also got a retcon panel saying Catherine died of an illness instead of an OD. This would have been a fascinating storyline. Willis was mostly forgotten until New 52 where he's gotten the most focus and some rather curious mentions. I'm still not entirely sure just how Scott Lobdell sees Willis (*1) but I'm interested in seeing more. Plus with Jason reliving the events of DITF it should be interesting to see how the whole mother plot plays out in this canon.
*1 Jason isn't always a reliable narrator and seemed to be avoiding certain things For example Catherine appearing pregnant which he never mentions and supposedly was going to led to a storyline involving a little sister that was scrapped. Makes me wonder what else we weren't told.