For me, the problem was story. The whole 9/11 angle seemed to muck things up far more than advance.
I'm not one of the 'it was x years ago, so stop talking about it' crowd. Lost a family member that day, as it were.
But in the ensuing years, I now live near the widower of that family member (reminder: lots of firefighters are women), and we both agreed this was enough of a stretch to make those people sound pretty rational.
Recorded his words for accuracy: "If you take 9/11 away, it's probably about the same story. Good story. Just didn't like that they used the towers like that. People only got real riled in the dinner part and that's not how it was back then. You {this writer} were only in college, but I know you remember how people popped off all the time right after."
In short, 9/11 seems more a convenient linchpin than a properly explored central theme.
That said, the direction resulted in some excellent on-screen chemistry from the leads - which I barely believe wasn't there already. Also a surprising number of beautifully shot scenes with actors present - infinitely harder than without them. And despite my thematic disagreements, some tight writing.
Film gets a 5 from me, but might have been a 7 if personal circumstance didn't prevent an objective view of the subject matter.
Scoring as the latter because: won't hurt your rating on account of personal history, and hopefully a higher rating gets this film more viewings, especially from those of us connected to the event, that it might challenge us to think differently.