The theatrical release of Batman v Superman: Dawn of Justice didn't have scenes in the traditional sense. Information was rationed out in condensed, discordant blips that sat awkwardly in the assembly. Story didn't develop naturally, people and identities came and went as the action demanded, and no-one but Ben Affleck's Batman was allowed a distinct point-of-view. This had the cumulative effect of saddling the caped crusader with the role of the protagonist, a job that the character, as presented here, couldn't shoulder without seriously unbalancing the film.
Dawn of Justice's Batman is reactionary and paranoid, a man dealing with survivor's guilt by putting himself on a collision course with an alien who dwells in the sky. The cinema release did such a poor job of communicating the virtues of Henry Cavill's Superman that the film couldn't help but fall in line with Bruce Wayne's blinkered world view. There was no alternative. Worse still, his mission, the film's backbone, is founded on misinformation planted by Jesse Eisenberg's Lex Luthor. Batman wasn't even the master of his own destiny.
Action films demand heroes that express individuality, it's their defining trait. They're going against the grain, betting everything they have on their ability to succeed. Action films, and the hero myths they are descended from, are a way in which human culture expresses the desire to be special, to be unique and lauded amongst your peers. By founding Batman's goal on a willingness to be manipulated so thoroughly, the filmmakers abdicated Wayne's prime positioning. They'd made him appear weak just to twist the knife. Power does not reside with this Batman. He's old and misguided, tragic even.
Lex Luthor then is crowbarred into an authority role that the film doesn't account for. Lex is a cipher, a colourful Google era recontextualisation of Superman's stock, big business bad guy. He isn't supposed to drive the film, he's an irritant. In the theatrical cut of Batman v Superman, Luthor gloating is the most powerful moment in the whole piece, it up-ends assumptions and throws everything into chaos. In this Ultimate Edition it's nothing. The weight of the revelation matters less because we already have another character bearing narrative weight - Superman.
Theatrical Superman plays solely into his omnipotent powers - he was everywhere he needed to be, armed with an opinion. He wasn't a person, he was an obstacle. Ultimate Superman we discover isn't really Superman at all, he's a different expression of Clark Kent. Ultimate's biggest addition is the clarification that the Kent persona isn't just a disguise or a hobby for this stranded God (think Hellenic, rather than just Judeo-Christian), it's the true expression of the man. He wants to be good, to make his Dad proud. He also cares about journalism as something beyond access and the opportunity to hang out with his girlfriend.
In Zack Snyder's longer cut Superman is pitted relentlessly against apathy and outright bigotry. Mankind is portrayed as teetering on the edge of damnation, a people motivated by small, petty emotions that appeal to their inherent hate. Personal prejudice rules; facts and data a distant consideration. In this milieu, Affleck's Batman is finally allowed to assume the position he was always designed for - he's the antagonist, the ultimate, mechanised expression of reactionary political posturing. Removed from the responsibilities of the leading man, it's fun to watch a Batman so damaged that he's happy to move on convenient truths and outright lies. Simply, he's scared.
The Superman persona then is something truly distinct, and perhaps even unwanted. It's a role that Kent assumes not out of joy or even necessity, but out of guilt. He knows he can help. The confrontation with Batman isn't motivated by the hypocritical urge to tidy away the human vigilante, the greater detail here points to a Superman that is alarmed by a man who doesn't even try to understand the consequences of his actions. In that respect, Batman becomes a personification of all this film's oozing, capricious humanity. Bruce Wayne is oblivious and indulgent, filled with certainty and acting without any thought or consideration for what Superman brings to the world.
Batman v Superman is no longer a pro wrestling dream match, it's a misanthropic suicide pact between two broken idols, disgusted by the world that surrounds them (see also - Optimus Prime in Transformers: Age of Extinction). This viewing, when Batman intones "You were never a God, you were never even a man." he might as well be talking to himself. He knows he's gone too far, he's working against his mission, betraying his vow to Gotham and his dead parents to appease his bruised ego. By apportioning equal time and motivation to Superman we get a fresh perspective on a Batman desperate to be swept up and saved.
The deletion of Superman's path to this fight robbed Batman v Superman of its sense of tragedy. Martha Kent's rescue is not only the film's emotional climax now, it's the moment a bitter enemy redeems himself, finding purpose working alongside an altruistic superhuman whose last thoughts were of his mother. The chivalrous, Arthurian imagery present in the superfluous CG crescendo that closes the film has been given purchase in something other than an Excalibur poster outside the Wayne family's death cinema. They're the model for future films - Knights without countries finding common cause fighting for the ideals of a God that died for his adopted planet. Batman's promised Justice League seems less like an economic imperative and more like a logical progression from the moment an alien made Bruce Wayne feel small then ashamed.