Miss Ellie Ewing in Dallas
Through the many seasons of television's most iconic 1980s soap opera, the steadfast and strong Miss Ellie Ewing – played by Barbara Bel Geddes – was a safe haven from the storms of Southfork ranch, and a family touchstone for the generations-old Ewing dynasty who ruled it. That is, until someone had the mad idea of handing the role to Donna Reed during Bel Geddes' absence from the production for health reasons and, in an instant, and with no in-universe explanation, the weeping Miss Ellie at dying Bobby's bedside changed faces.
Becky Conner in Roseanne
Lecy Goranson (left) was replaced by Sarah Chalke in Roseanne.
After being well established as the older of Roseanne's two daughters in the hit sitcom of the same name, actress Lecy Goranson headed off to college in real life, forcing the producers to recast the role. Sarah Chalke wasn't bad, she was just ... different. It didn't go down too well with the audience either, and Goranson returned a season later, though she and Chalke subsequently alternated and, on occasion, the show's writers made light of it with occasional references to the fact that the two girls, while both blonde, looked quite different.
Herr Otto Flick in 'Allo 'Allo!
Richard Gibson was replaced by David Janson in 'Allo 'Allo!.
Of all the hopelessly cliched characters in this brilliant parody of the British drama Secret Army, the town's resident Gestapo boss, Herr Flick, was perhaps the bluntest. Richard Gibson played him with limping, twitching brilliance for most of the series until, inexplicably, the role was recast with David Janson who, compared with his predecessor and saddled with doing an imitation of an actor who was himself playing to a cliche, didn't measure up.
Roman Brady in Days of Our Lives
Wayne Northrop as the original Roman Brady in Days of our Lives.
So, the role of Salem's resident cop and all-round good guy Roman Brady was originated by Wayne Northrop. That is, until he left and actor Drake Hogestyn came to town as John Black, a mysterious man who was later revealed to be Roman Brady. Except he wasn't, so he stayed John Black and Northrop returned as Roman Brady. But wait, there's more. Then Northrop left and the producers decided to recast with actor Josh Taylor, who had spent decades playing Salem bar owner Chris Kositchek. Say, what? Worst. Recast. Ever.
Amanda Carrington in Dynasty
Catherine Oxenberg (left) was replaced by Karen Cellini in Dynasty.
Though Dynasty pushed through a whole bunch of recast roles, notably Steven Carrington (first Al Corley, later Jack Coleman) and Fallon Carrington (first Pamela Sue Martin, later Emma Samms), it was their third go-round which seemed to bring things unstuck. British-accented actress Catherine Oxenberg exited the role of Amanda Carrington during a blazing fire, and was replaced by Karen Cellini, who came with no experience, bad hair and an American accent. Dynasty asked a lot of its audience over the years, but Amanda 2.0 sank quickly.
Darrin Stephens in Bewitched
Elizabeth Montgomery and Dick York in Bewitched.
Typically when a role is recast, an attempt is made to capture the spirit of the predecessor. In the case of Bewitched's revolving Darrins, the two actors could not have been more different. When Dick York originated the role, Darrin was an awkward, neurotic, twitching mortal spouse for Elizabeth Montgomery's supernatural Samantha. York exited for health reasons, and while Dick Sargent stayed in the role until the series wrapped in 1972, his Darrin was calmer and lacked the neurotic brilliance of his predecessor.
Kathryn Janeway in Star Trek: Voyager
Kate Mulgrew (centre) in Star Trek: Voyager.
This one works in reverse – it wasn't the replacement that was startling, it was the original. When Paramount launched this Star Trek spin-off, it was actress Genevieve Bujold who starred as Captain Kathryn Janeway. Midway through filming the pilot, however, Bujold resigned. A statement from the producers said Bujold had "realised that the rigours of episodic television were too demanding". Media-shy Bujold never elaborated. The role was then given to actress Kate Mulgrew.
Jan Brady in The Brady Bunch
The Brady Bunch Variety Hour.
Eve Plumb, who played the middle daughter of television's most beloved family, returned for a sitcom spin-off (the telemovie The Brady Girls Get Married, which turned into The Brady Brides) and most of the subsequent Brady reunions, including the notable A Very Brady Christmas, but passed on the short-lived, and fairly startling The Brady Bunch Variety Hour, in which they all donned flares and sang. Smart girl, no? Plumb was replaced for that series by Geri Reischl, a move which seemed for many years to fuel rumours that Plumb had died.