Since the DCEU places the character of Bruce Wayne 20 years late into his career (middle aged), it would be a legitimate choice to have the likes of someone in the industry like Olivia Wilde to play one of the Bat-Family members in her young adult stage in the mythos.  Not only this, but Ms. Wilde is a very accomplished on screen actress starring in various roles that have required her to play strong, street smart, good spirited and highly intellectual young women in popular films and TV series.  Combine all of this with the fact that she looks very much like the comic book figure of Barbara herself gives all the more reason of why she'd be one of the best and most faithful candidates to do justice towards such a timeless DC hero.