At what point do you think if a movie is going to be bad before it releases?

What the title says.

Over here we tend to track the production of movies right down to every rumour and scoop whether it's a comic book movie or not. What's the point where you think it's going to suck?

Would it be things like Drew McWeeny's BvS rumours? Set drama rumours involving Josh Trank in Fan4stic? Heavy studio interference like in Suicide Squad?

At what point do you think if a movie is going to be bad before it releases?