I'm actually a fan of longer cuts for such movies unless it absolutely doesn't demand it. And with superhero movies there's usually enough material from the comics to make for an extended cut. Which is why I wouldn't mind an extended version of Justice League (regardless of whose 'version' it is) because the movie as a whole was pretty fun.
That said, I didn't share the same opinion for the extended BVS cut (which I didn't watch) because the main film felt so irredeemable that I didn't see the point.