Although Whedon's switch from Marvel to DC was heralded as something positive for the DCEU going forward, the release of Justice League has dramatically tempered those expectations.
Brought in to finish the ensemble once Zack Snyder departed due to personal circumstances, Whedon purportedly reshot extensive portions of the film in the months leading up to its November premier. There are plenty of shots from the film's trailers that never saw the final cut, and while Snyder's work has been criticised in the past - none more vociferously than his contributions to WB's cinematic universe - it's debatable as to whether Whedon's amendments improved upon his initial concept.
Indeed, it's more likely that the Avengers man actually had a negative impact upon the film. The reshoots are obtuse and distracting, and eliminate certain sequences from the trailers that, at one point in time, provided cause for excitement regarding the feature. That, and they also lend the film a kind of plastic feel, one that - ironically - WB had been trying to free itself from with his appointment.
With calls for a release of Snyder's cut now mounting, a case could soon be made that the Watchmen director's original vision (once dubbed 'unwatchable' prior to release), was superior to his colleague's. If that is indeed the case, then a departure from Batgirl could and should be discussed.