First aired during the golden age of the miniseries, the much-acclaimed, much-nominated Shogun remains one of TV's highest-rated miniseries. But now that it's finally on DVD, it's hard to see what the fuss was about. This plods as ploddingly as an epic can plod. Based on James Clavell's best-selling 17th-century saga of a shipwrecked English seaman (Richard Chamberlain) who serves as a samurai under a powerful warlord (Toshiro Mifune), the story is not so much dramatized as it is laboriously reenacted. All journeys, even those up flights of stairs, are documented in painstaking detail. Also slowing things down are a forbidden-but-fairly-chaste love story, mini-lectures on 17th-century world history, and some very occasional stilted action. Yet everyone in the making-of doc is still complimenting each other on a ''masterpiece'' well done, while in his skimpy commentary director Jerry London seems more concerned with how the film looks than how it plays. He should be: From its stunning Japanese locations to its lavish costumes and sets, ''Shogun'' visually evokes a world that the narrative rarely brings to life.