Hawks, I just think the Loki-Ultron-Steppenwolf story lines are too much the same. The heavy hitters go up against the main guys while Cap, Hawkeye, Widow, Batman, go up against the residual armies. JL vs IL could be awesome - the only concern would be that might be too much content to show 4-6 major battles.The more I think about it, it does feel like a different version of Superman in JLA. Seemed to a be a lighter/more hopeful version that lines up with the character better.
I really hope they don't go that route, I'd much prefer to see Darkseid in the next movie if it gets made.