I agree with you on the merit of John Hough's THE LEGEND OF HELL HOUSE (1973), which I consider the greatest haunted house film ever made – even better than Robert Wise's much-vaunted THE HAUNTING. Now and then a journeyman director like Hough will create a masterpiece and this certainly is the case here. Which makes it all the more puzzling why his previous effort, TREASURE ISLAND, is such a fiasco. Perhaps this is due to the Welles curse or to lowbrow producer Harry Alan Towers' meddling. Not to take anything away from Hough's contribution to THE LEGEND OF HELL HOUSE, but the director was working from a solid Richard Matheson screenplay, based on the author's searing novel HELL HOUSE, which in turn derives from his scary 1953 novella SLAUGHTER HOUSE. And HELL HOUSE's cast was absolutely top-drawer: Roddy McDowall as the frightened psychic, the sole survivor of a previous expedition to "the Mount Everest of Haunted Houses"; Clive Revill as a smug scientist intent on disproving occult forces; his straight-laced and increasingly lascivious wife (Gayle Hunnicutt); and Pamela Franklin as an "accident"-prone mentalist who is fatally attracted to a ghost seeking the light. One must also cite the eerie electronic score by Delia Derbyshire and Brian Hodgson, the opulent sets by Robert Jones and the dread-inspiring cinematography of Alan Hume, which induces a most peculiar feeling of claustrophobia and depression – suitable for an evil house that has witnessed "drug addiction, alcoholism, sadism, bestiality, mutilation, murder, vampirism, necrophilia, cannibalism, not to mention a gamut of sexual goodies," as McDowall's character explains.
Damn it all, I'm going to come right out and say it: THE LEGEND OF HELL HOUSE is better than any film ever directed by Orson Welles, and that includes CITIZEN KANE. It's certainly better than NECROMANCY (1972), in which a caped, putty-nosed, granny-glass-wearing Welles starred as a deranged toymaker.
So therein lies the mystery: why wasn't Hough able to pull off this coup de théâtre a second time? With the odd exception, just about everything else the man directed was forgettable.