The blame for these issues does not fall on Megaton or Saldana, but rather the last person I would expect: Luc Besson. Besson has done a great job writing screenplays for these types of films before (EX: District B13), but he just really dropped the ball on this one. Megaton and Saldana do the best they can with the material given, but this material unfortunately includes lines like: "she's like a mist, you can barely see her" and a romantic subplot which makes borderline no sense whatsoever.
We are expected to believe that Cataleya has a boyfriend who is completely in love with her despite not knowing a single thing about her, while their relationship only seems to involve having sex at night and her leaving in the morning. Cataleya never seems to return any of the affection her boyfriend is giving her, so why does this relationship even exist? I've noticed a recent pattern of action movies bringing unnecessary relationships into their plotline, and movies like this are evidence that it needs to stop.
It's hard to talk about the acting in this film, because there really isn't too much "real" acting. Zoe Saldana shows up, looks hot, kicks ass, does a little cry, and then goes home. The only person who appeared to be doing anything interesting, was Amandla Stenberg, who played Cataleya at age nine. She was able to convey Cataleya's lust for revenge in fifteen minutes better than Zoe Saldana could over the course of the entire film.
Despite hearing in advance that the majority of reviews were negative, Colombiana was still a major disappointment for me. When you enter the theater expecting to be entertained by dumb action if nothing else, and it even fails to deliver on that front, it feels like you've just wasted your time. And for Megaton, Saldana, anyone who sees this film, and me, it probably was.
*Note: Isn't the last name Megaton the ultimate action director last name? You could get a career of that alone.