I do believe that the Batman Inc epic is going to finish up with the Heretic being .... BANE. and since we just got Bane in DC 75 and Talia (leviathan) in the same set or BatB (I think) that explains for why we might not have seen them show up in the Batman set.

Why is the Heretic Bane? ... Right size, a legit threat, has a respect/ hate relationship with the Bat family, plus the heretic was essentially on drugs when we first saw him.

That is a VERY interesting theory. I avoid Grant Morrison like the plague but I still follow up on Inc because it is an interesting property.

I've heard that Bane theory, and in tone, it certainly fits with the kind of reveal we got regarding the identity of Wingman, so I suspect you are probably correct.

Another theory (not mine, I can't claim this as my own) I have heard floated around here and there...

I'd be shocked if it's anyone other than an aged clone of Damian.

I'll bet good money that it's not Bane.