We don’t know exactly what the issues were, but there are some aspects of the show that have changed since he left.
The original showrunner, Ben Queen, left the series last summer over “creative differences” with Warner Bros. TV.
A good portion of the Powerless pilot episode was reshot, to better reflect this shift in plot.
We know that the show will give nods to characters like Batman, Superman, Joker and Wonder Woman, but it remains to be seen what other heroes and villains will be referenced.