I would love to see Croc, but as a supporting character.
My favorite Batman story is Batman: Broken City. The usage of Croc and the depiction of him in that book is pitch-perfect. He'd work perfectly as a secondary/tertiary villain/character in the next franchise.
On that note, I'd also love the noir voice over/inner monologue of the Batman like in a graphic novel in the next film... Make it different from the last seven Batman films.
-R