Re: All Things Superman and Batman: An Open Discussion - - Part 11
If it's an after credits tag then I think it would be fine. However I'd be much more skeptical of adding it onto the end like the Joker tease in BB. For BB that was more natural since it was Batman's nemesis and a continuation of his story. I think it would be another thing altogether to tag onto what is hopefully a stand alone story for Batman/Superman with a tag to a whole other franchise like the Justice League or even the next Batman solo.