Why this movie failed...
First, Cusack's character is a stubborn boy scout, and nobody likes a stubborn boy scout. By the way, I mean "boy scout" in the cultural colloquial way, not a real Boy Scout. Real Boy Scouts are cool, fun, reliable and tough individuals, I know because I have one for a son.
Second, making Morgan Freeman the "bad guy". Morgan Freeman is so incredibly beloved in the U.S. that no one can see him as a bad guy that you would root against. Now, he can be a bad guy, but only a bad guy that we want to see succeed. He is similar to Cary Grant in that respect. As a matter-of-fact, Freeman is probably as close to Grant's beloved status as any actor working today. Bottom line, you put Cusack against Freeman in a movie, no WAY is the audience going to root for Cusack. Freeman is simply too well liked, a much better actor, and Cusack is just too much of a smartass. Now, sometimes this is great, everybody loves the movies where Cusack is a befuddled smartass, trying to make his way in life with everyone taping a "Kick Me" sign on his back. However, you put Cusack in a movie as the "good guy" against Freeman's "bad guy", people will root for Freeman every, single, time. This might work in some movie's, but in this movie it was counter-productive to the narrative. Personally I think the script was changed late in production, perhaps even re-shot after a test screening, because suddenly Freeman's character becomes a "good guy" and becomes the protector of Cusack and his son. It just seems tacked on.
Third, the movie takes great pains to convince us of the bad-ass-ness of these five assassins, and then it allows all but one to be killed by little 'ole ex-cop, P.E. teacher Cusack. The worst one was the first kill of Cusack's, where the "tracker" character shoots Cusack and walks up saying, "I hate amateurs" and gets shot. NO WAY the guy wouldn't have pumped a few shots into Cusack lying there on the ground. So, the character development actually becomes contradicting, AND it causes us to actually root for the bad guys. We are irritated that little Cusack is winning, when we have been shown how bad these guys are.
Last, Cusack's character puts his son's life at risk in trying to "bring in" Freeman. We cannot sympathize with Cusack's position, or even for his angst over his son because HE got himself in this mess trying to be Mr. Big Hero. For ANYONE who is a parent, this is unforgivable. Cusack should have simply walked away as Freeman said, he had NO business putting his son in harms way by acting like he is big and bad.
Casting could have EASILY corrected these problems and possibly fixed this picture as is. They should have used a guy that isn't so beloved as the bad guy, and a guy not associated with being a smartass as the hero. Or they could have changed Cusack's current job to that of a off-duty cop, or ex-special forces or something. But the biggest error was Freeman as the bad guy, he is a national treasure and can never be someone we are rooting against... ever.
"...nothing is left of me, each time I see her..." - Catullus