First, it's a compelling movie. The fact that I kept watching (I came in where Ben Affleck is trying to convince Samuel Jackson to take a blank check) rather than flicking to another channel indicates the plot's attraction. I'm not a big Ben Affleck fan. But I was drawn into the story of these two lives paralleling each other, meeting, crossing over and paralleling each other once again. I don't care for greedy, evil law firm cliches in my films, but the particular evil--the fraud--of Gavin's law firm was quite realistic since it wasn't outright evil, just a lack of any moral sense. (And made a kind of logical sense, shorn of ethical considerations.) In the same way, the immorality of Gavin's "threat" to Doyle was much more realistic and devastating than if he'd brought in the mafia. And the idea that these two men had placed themselves on paths that got increasingly morally complicated as they made increasingly poor choices was, well, rather enlightened and pro-free will (not a usual Hollywood trait). Refreshing, frankly. (I was impressed by how few people in the movie let Doyle off the hook, despite him being, initially, the offendee rather than the offender. I did think William Hurt was massively underused, although perhaps he showed up more in the non-TV version.)
However, the ending was, well, I'm not sure. On the one hand, I liked how the two lives finally came together and worked themselves out. On the other . . . so much for free will, enlightenment and people making moral choices. Doyle does change his life (and is the more appealing character of the movie) but Gavin goes from being an amoral patsy to being an amoral force. He doesn't really "change lanes." He just entrenches himself. Which may be the point of the movie, but if so, it goes against the overall theme. It's as if the writers/producers wanted to present the end result of living amorally but couldn't bring themselves, in the end, to advocate any kind of actual morality (such as the "contract" of decency that Hurt very effectively throws at Doyle.) It's as if, having shown us how totally terrible simply reacting to circumstances (rather than being guided by a moral code) can be, they nevertheless decided to side with Gavin's boss: it doesn't matter what you do so long as you do "more good than bad." (Rape, pillage, murder but give $1 million to starving children and you're a great guy! It's the buy-yourself-out-of-hell version of reality.) And although Gavin's "blackmail" at the end of the movie is effective plot-wise, it doesn't make sense that his intervention for Doyle would then work. Unless Gavin had truly "changed lanes," Doyle's wife (no amoral patsy) would never give him the time of day.
Maybe this ambivalence is Hollywood. Everybody says it's Hollywood. I don't know. I'm not sure people are that confident (or ever have been) about morality, which is why fundamentalism either attracts people or freaks them out. We just don't know what to do with it all. In any case, an otherwise compelling movie about moral choices is turned into yet another "he with the biggest stick wins" lesson in which amoral, powerful people are considered good and wonderful so long as they want good and wonderful things like pro bono work and a clean environment. Which makes you wonder whether Hollywood has any clue at all about how a democracy, or the middle class, works. (It is possible that the writers wanted Gavin to come off as a kind of Dr. House: that is, a guy who will take on the corrupt world as it is. All very Catholic and fatalistic and original sinish. However, Dr. House is never afraid of the fall-out of his choices, even the possibility of killing a patient, and Gavin patently wants to avoid that fall-out; I mean, the guy should have gone to jail, patsy or not.)