I actually really enjoy Justice League. It's an easy watch, and a fun movie. It completely delivered so far as I was concerned (will not say that about Batman V Superman: Dawn of Justice however).
ANYHOW, if there's another cut out there or they can cobble another one together including footage like this I would be extremely fired up to check that out as well.
Here's a piece I read about all of this for that matter. It's a shame to me that we'll either never get Justice League 2 at all or at least that Ben Affleck has already exited the Batman role with Henry Cavill probably done with Supes as well.
I will, however, sign off on a follow-up that centers around Aquaman, Wonder Woman, and Shazam! if they want to go that route. Bring back Cyborg and Flash for that one too.