Okay who takes this 2 vs 2 all out battle ? The fight takes place in New York City and both team know they are coming.
What can the Riddler do? Of course he can have the Joker and Two-Face walk into a death trap. But in combat, what? The Joker can use his guns, gadgets, and toys against his foes. The riddler can...Well, make riddles... The riddler is a boring character anyway.