Killer Croc is in the upper echelon of Batman enemies. It might not come across that way, but in terms of name recognition - especially thanks to the Arkham games - he outstrips all but the biggest villains at this point. I'd say he's probably better known at this point by the general public than Clayface, Man-Bat or Deadshot. But his role is, universally, "the big dude for Batman to take down before fighting the real guys". I hadn't known he'd ever been anything else until I read a piece of Jason Todd's original origin, where he was shown as a scaly-skinned gangster. Generic, but immediately more interesting and promising than the regular guy had ever been; Mark Waid couldn't even do a good comic with that guy.
Should that be the gimmick to finally make something worthwhile of the character? A 10-foot, green-skinned tuxedoed madman with a taste for human flesh who nevertheless manages to get out solid instructions for his lieutenants to carry out between his roaring and occasional devouring of random henchmen, and fancies himself the underground King of Gotham and Batman's rival. Kingpin as black comedy. Any takers?