I will say James doesn't look much like Jesse Custer. However, in terms of the story and in terms of the material I believe he could've pulled it off amazingly.
In the end, this is on topic and did involve Marsden at one point. For those who want to find out more about the Preacher, here is some information about the story.
Preacher tells the story of Jesse Custer, a down-and-out preacher in the small Texas town of Annville. Custer was accidentally possessed by the supernatural creature named 'Genesis' in an incident which killed his entire congregation and flattened his church.
Genesis, the product of the unauthorized, unnatural coupling of an angel and a demon, is an infant with no sense of individual will. However, as it is composed of both pure goodness and pure evil, it might have enough power to rival that of God himself. In other words, Jesse Custer, bonded to Genesis, may have become the most powerful being in the universe.
Custer, driven by a strong sense of right and wrong, goes on a journey across the United States attempting to (literally) find God, who abandoned Heaven the moment Genesis was born. He also begins to discover the truth about his new powers, which allow him to command the obedience of those who hear his words. He is joined by his old girlfriend Tulip O'Hare, as well as a hard-drinking Irish vampire named Cassidy.
During the course of their journeys, the three encounter enemies and obstacles both sacred and profane, including: the Saint of Killers, an invincible, quick-drawing, perfect-aiming, come-lately Angel of Death answering only to the authority of God Himself; a serial-killer called the 'Reaver-Cleaver'; The Grail, a secret organization controlling the governments of the world and protecting the bloodline of Jesus; Herr Starr, ostensible Allfather of the Grail, a megalomaniac with a penchant for prostitutes, who wishes to use Custer for his own ends; several fallen angels; and Jesse's own redneck 'family' particularly his nasty Cajun grandmother, her mighty bodyguard Jody, and the 'animal-loving' T.C.
For several years, a film adaptation by View Askew Productions was in the works, with James Marsden attached to play the lead. The project never materialized, although production got so far as to begin make up tests for the Arseface character, gruesome pictures of which can be found online. At one point, Samuel L. Jackson, a comic book fan, expressed interest in playing the Saint of Killers.
In May of 2006, rumors began circulating that the cable TV network HBO might produce an adaptation of Preacher. In late November, The Hollywood Reporter confirmed this, reporting that the network was developing a one-hour series with executive producers Mark Steven Johnson and Howard Deutch, the writing-directing team that brought us Grumpier Old Men. Johnson will also write the pilot.
Mark Steven Johnson told SCI FI Wire that he plans to turn each issue of the comic into a single episode, which will be as close to the original source material as possible. "I gave [HBO] the comics, and I said, 'Every issue is an hour,'" Johnson said at a preview of his upcoming film Ghost Rider in Hollywood, Calif., on Nov. 30. "And it's exactly the book. ... I had my meeting yesterday, and Garth Ennis is on the phone, and we're all in the room, and Garth is like, 'You don't have to be so beholden to the comic.' And I'm like, 'No, no, no. It's got to be like the comic.' So that's what's so brilliant about it. It's just like, HBO, who else would do it but them? Nobody. ... HBO is just like, 'Bring it on.'" Johnson has also confirmed that this will include the various one-shots and mini-series.
Considering what Mark Steven Johnson did to Ghost Rider, I'm very concerned about him even being near the concept.

Still would've been nice to see Marsden play the title role though.
