Writing about the past four seasons of HBO's The Wire has been one of the great pleasures of this job. But reviewing the fifth and final season, which begins next Sunday on the premium cable channel, is more of a mixed blessing.

It's not that the series has suddenly taken a drastic turn away from its epic and compelling exploration of life in a downsized Millennial America. Steeped in a dense and seething urban sociology, the Baltimore-based series is still one of the most daring dramas in the history of the medium.

Hardcore fans will find much to like in Season 5 - thanks to a greatly expanded role for rogue detective Jimmy McNulty and an intensely focused performance by Dominic West as the troubled Baltimore cop.

But while the police story line has never been stronger, the first seven episodes made available for preview contain nothing that matches the emotional power and sociological insight of the show at its best - namely the classroom scenes from Season 4.

The complicating factor for me is that creator David Simon turns his lens to the media this season - with a particular focus on a fictionalized version of The Sun newsroom. (Though some scenes were shot on Sun property, the paper did not review the scripts or have any involvement in the production.)

Whether I praise or pan Simon's made-for-TV version of the paper, the fact that I work for The Sun means I am likely to be mistrusted, if not damned. So be it - I am not the first journalist to write about matters involving his or her own paper.

And the newsroom scenes are the Achilles' heel of Season 5 - with mainstream entertainment sacrificed to journalistic shop talk, while fact and fiction are mashed up in the confusing manner of docudrama.

There is greatness in the seven episodes, especially when the series leaves the newsroom and returns to the streets. The scheming and showdowns featuring such larger-than-life characters as Proposition Joe Stewart (Robert F. Chew), Marlo Stanfield (Jamie Hector) and Omar Little (Michael K. Williams) have the scope and thunder of a Sam Peckinpah Western.

Simon didn't invent the idea of the urban landscape as a new American frontier. But starting with HBO's The Corner, he was the first not to reduce all people of color on that landscape to one-dimensional stick figures and then demonize them.

As the season opens, Omar has left Baltimore for sunnier climes, while Marlo schemes and Joe tries to hold his shaky drug co-op together. There has never been a cast of TV villains as multi-textured, menacing and engaging as this.

One reason they are so fascinating is that Simon made viewers see them as human beings - and, in some cases, even care about them.

Meanwhile, life is worse than ever at the cop shop. Baltimore's calculating mayor, Thomas Carcetti (Aidan Gillen), has cut the department's budget to the bone in an effort to cover his promises of more money for city schools. As a result, police are operating without overtime - and, in many cases, without cars and radios for some officers and detectives.

Angered by such diminished circumstances, McNulty is drinking and carousing again. Before long, he is totally off the rails and headed down a dangerous road of deception and lies - that will bring him into league with an unscrupulous reporter at the dramatized Sun.

Time and again, momentum is lost as the story shifts to the newsroom. Part of the problem involves the way Simon populates the city room with several non-actors.

Two of the first Sun staffers that viewers will see are played by former Sun columnist Michael Olesker and former feature reporter Laura Lippman. They look like two people stuck in cement before the camera mercifully leaves them behind. (Lippman is Simon's wife.)

Ed Norris, the former Baltimore police commissioner who plays a homicide detective on the series, is not an actor either, of course. But he has a natural energy and raw anger that are in perfect sync with the dominant sensibility of the series.

Other former Sun staffers with speaking parts include Scott Shane, now with The New York Times, and William F. Zorzi, who is a writer on the series. Zorzi's role is much larger than his onscreen talent.

Beyond Simon casting on the friends-and-family plan, there are other - more serious - problems with the newspaper story arc.

The best thing about the narrative is that it stars Clark Johnson as Augustus "Gus" Haynes, a no-nonsense city editor. Johnson, who was superb in his understated depiction of Detective Meldrick Lewis on NBC's Homicide: Life on the Street, enlivens every scene in which he appears.

But Simon, who is so skilled in creating multifaceted characters elsewhere in the series, makes Haynes a one-dimensional figure without flaws. He is a repository of all things good when it comes to big-city newspapers - things that the series claims have been mostly lost in devotion to the bottom line by media corporations.

Almost everyone in the newsroom is a cardboard character - in part because Simon writes it like a morality play. Just as Haynes is goodness, the villains are pure duplicity and evil. It is difficult to get involved in the lives of such characters - unlike last year, when poignant classroom scenes led viewers to care about deeply troubled but highly promising teenagers.

More problematic still is the way Simon links certain newsroom characters to real-life journalists through words and actions - and then depicts them exclusively in a negative fashion. Simon moves deeper into docudrama when he does that, and The Wire suffers as a result.

The docudrama genre, which has come under increasing fire in recent years, combines the look of documentary film with the literary license of theater - giving viewers the sense that what they are watching is true even though facts have been rearranged and actions invented.

Beyond blurring fact and fiction and ignoring any sense of proportionality, the genre also telescopes and confuses time. Simon left the Sun in 1995, and his newsroom villains are patterned on editors and a reporter long gone from Baltimore. But Simon presents his story as if it is taking place at The Sun today.

Ultimately, the most disappointing aspect of Season 5 is that Simon offers such a simplistic critique of media and their effects on mass consciousness. To say that even the most respected newspapers sometimes have ethical lapses will hardly be news to any HBO viewers who have ever heard of Jayson Blair and The New York Times.

Newspapers have changed exponentially since Simon left 12 years ago. When he was in the newsroom, cable TV was still considered new media - and most newspapers were at least five years away from the realization that they would soon live or die by the Internet. The first seven episodes of The Wire have almost nothing to say about the biggest story in newspapers: the vast technological change sweeping through media today. And that is most surprising given how up-to-the-second - even prescient - the series has been about the use of the latest technology by criminals.

Perhaps the final three episodes - the ones HBO has yet to make available - will redeem the newsroom story line and form a glorious ending for The Wire.

Here's hoping that is the case. Not just for the enjoyment and illumination of its fans, but this writer as well, who has found such delight over the years in celebrating this landmark show.

david.zurawik@baltsun.com