Joss Whedon is not shying away from the fact that he is done with the Marvel Cinematic Universe. He also seems as if he would direct a DC movie should Warner Bros. require his help, but we doubt he will ever get that opportunity again.
Yes, we say "again," because back in 2005, Joss Whedon was picked up by Warner Bros. to direct Wonder Woman. He provided a script, so it came down to the studio giving it the green light. However, that did not happen, and Whedon went on to make a success story out of Avengers and Age of Ultron.
However, that is not stopping the famed director from wanting to work on a DC project again. In a recent interview with IGN, he made his intentions clear, though he is not confident if his ideas would fit into where Warner Bros. want to take the DC Cinematic Universe.