It seems like the DC Cinematic Universe has been plagued with problems. The Batman standalone picture has gone through a number of screenwriters and some director turnover; Suicide Squad; Batman v. Superman (I'm not pointing out anything in particular with those last two films; they themselves were problems).
Then in the middle of reshoots, Justice League lost director Zack Snyder because of a family tragedy. Joss Whedon stepped in to finish the film, and that has people worried. Snyder and Whedon have very different aesthetics, so there is some concern about how the scenes from different directors will fit in together.
Ben Affleck, who plays Batman in the film, isn't worried. He recently told EW.com:
“It’s a little bit unorthodox. Zack had a family tragedy, and stepped off, which was horrible. For the movie, the best person we could’ve possibly found was Joss. We got really lucky that he stepped in.” Affleck went on to describe Justice League as “an interesting product of two directors, both with kind of unique visions, both with really strong takes. I’ve never had that experience before making a movie. I have to say, I really love working with Zack, and I really love the stuff we’ve done with Joss.”
This doesn't necessarily mean the movie will be good. Affleck isn't saying that the finished product is good. He likes what each director produced, but will they work as one single film?
Affleck finished off his interview with this: “This is a really nice time to work in DC. They’re hitting their stride. They’re getting it right. It’s starting to feel like it’s really working.” As far as I'm concerned, this is coded company-man talk for "Yeah, I didn't like Batman vs. Superman all that much either."
Justice League is scheduled to arrive in theaters November 17.