I expect it to be better.
I do not, however, expect it to suddenly become good.
Pixar's "Up" told in 10 minutes a complete story of two children who fell in love, established their bond and connections, their motivations and interests, their personalities and flaws, and chronicled their entirely lives together through the highs and lows of a transformative marriage that ultimately ended with loss and heartache, giving both leads a complete, solid, understandable story arc to follow and setting the stage for the adventure to come in the rest of the film.
Having watched BvS, they weren't able to clearly do this in over two and a half hours.
Adding 30 more minutes might help, but the fact they couldn't do it the first time, and yet there was so many boring, dull, pointless shots and slow-mo in the first incarnation, just tells me they didn't know how to tell a coherent story with believable characters with nearly 16x the runtime of Up's opening 10 minutes.