6. Lay Strong Justice League Foundations
With Superman and Batman as the titular characters and Wonder Woman, Aquaman and Cyborg all showing up in this movie, that simply can't be wasted by not using it as a catalyst for expansion. We seriously hope that the likes of Wonder Woman, Aquaman and Cyborg aren't just in this movie for the sake of it (for example, a scene in S.T.A.R. Labs in which someone called "Victor" has a five second conversation). Their appearances need to clearly express an intention to form the Justice League in future movies. Although we are obviously aware that the formation of said team is definitely going to happen, that groundwork needs to be clearly laid so that this movie makes us excited for the future. That said, it definitely needs to be done in a way that doesn't completely overshadow the main story of this movie - and that's the one that sees two epic heroes involved in a feud that culminates in what we hope will be one of the greatest showdowns in movie history.