I think I mentioned this before, but I always thought they were going to bring Aquaman into Batman v Superman for a cameo by tying it into Man of Steel.
There was that scene in Man of Steel, where the oil rig explodes, and Clark goes in and saves the workers, but yeah, the oil rig exploded, leaking tons of gallons of oil into the ocean. I always imagined Aquaman wouldn't be too happy with that. Although I always thought that perhaps it was Aquaman that sabotaged the oil rig himself, eco-terrorist style. I thought it would be neat to have a scene where Arthur confronts Superman about that event, or have Clark investigating acts of terrorism on the ocean, and it turns out its Aquaman trying to protect his people. Either scenario I felt would work better than what we ended up getting. I hadn't followed BvS, but I remember thinking that the Aquaman cameo would be a single scene like this, and Arthur then goes back into the ocean, not really interested in what Clark/Supes was peddling at the time, but could maybe be coaxed into joining their team during the Justice League movie, because the threat of Darkseid is so great that his oceans wouldn't be safe either.