The first time I've seen the longer cut, and unfortunately this isn't a case of revealing a classic mangled in the editing. In that sense, it's akin to Ridley Scott's longer version of Kingdom of Heaven; both films are crippled by clumsy scripts and bland lead performances. There's much to appreciate here; the cinematography is stunning, as are the sets. And Rob Bottin's creature designs are superb; it's the characters underneath that aren't up to much. In Alien, the skeletal plot allowed the director to infuse the film with atmosphere. Legend is also very slender in terms of (contrived) storyline, but there's nothing compelling at its core. All Scott's world building comes to naught because you don't feel he believes in any of it.
Scott is much too literal to make magic with the fantasy setting, and so humourless that he makes heavy weather of the comedy supporting characters (they utterly fail to be charming or appealingly silly - it actually makes you realise how smart George Lucas was with his comedic creations). The only bit player who lends a bit of verve to the proceedings is Robert Picardo's Meg Mucklebones. But he's only in the film for a couple of minutes. Mia Sara looks gorgeous, particularly when she's being tempted to darkness and dons black lippy, and her dance routine is one of the best scenes in the film. She also fares somewhat better than Cruise by ending up playing opposite the film's greatest asset; Tim Curry as the Lord of Darkness. He's aided by extraordinary prosthetics, but it's his performance that adds weight and drama to a film that was desperately lacking up to that point. Jerry Goldmsith's score, except in a few scenes, didn't do much for me; I think I prefer Tangerine Dream's work for the US version.
In general, the film picks up once we reach the lair of Darkness. Scott's more comfortable with the grime and grimness of the dungeons than the insipid extended Timotei advert of the early scenes, but for all its flaws there's still an admirable sense of a director stretching himself here. Following the failure of the film, Scott would retreat into the safety of contemporary thrillers for his next three features. His style would also become less about mood and atmosphere and more about high impact, cookie cutter editing such that you wonder if he didn't start paying too much attention to his younger brother.