Star Trek: The Next Generation debuted Thomas Riker.
Star Trek can be filled with odd and bewildering storylines at times. One story in Star Trek: The Next Generation saw William Riker discover he had a “twin” of sorts in Thomas Riker. A transporter accident occurred prior to Encounter at Farpoint, which saw William Riker get split into two different people. Identical in every way, but one was left on a deserted planet, while the other remained on board the U.S.S. Potemkin, the ship Will Riker served on until his transfer to the U.S.S. Enterprise.
Thomas was eventually discovered in the sixth season of Star Trek: The Next Generation, who was still going by “Will” at the time. He’d change his given name to Thomas, the Rikers’ middle name, and would try to get back to normal.
While ultimately Thomas Riker was brought back for a Deep Space Nine episode where he’d impersonate Will and join the Maquis, that was essentially it for him. In Deep Space Nine, Thomas is eventually found out and arrested, having been left in a cell where canonically he still remains. While the show went “evil twin/clone” real fast with him, he wasn’t supposed to end up that way. In fact, his creation could’ve shaken things up radically.
Thomas Riker was kicked around as a way to kill off William Riker in TNG
According to Larry Nemecek in the Star Trek: The Next Generation Companion book, Thomas’ creation stood in the way of keeping Will alive. An idea was seriously considered of killing off Will Riker and replacing him with Thomas on the ship. Thomas was a lieutenant at the time of the accident, and since he wasn’t discovered for eight years, he would still be the same age as Will and actor Jonathan Frakes but would be several positions rankings lower than Will.
This would’ve helped refresh the series. Had Will died, Thomas would’ve become a member of the bridge crew, with Data becoming the new first officer of the ship and Thomas more than likely taking Data’s original place on the ship.
For former show writer Ron Moore, the idea of replacing William with Thomas was a chance to reinvent the character. It was, however, eventually shot down by Michael Piller. An idea that would’ve given fans something interesting.
While the story of Thomas replacing William isn’t new, the least talked about part of the whole idea is how it would’ve affected things for Data and his placement on the crew. Depending on the episode, Enterprise captain Jean-Luc Picard treated Data as a pet, toy, friend, or child. Seeing Data being given more autonomy would’ve created a serious relationship shakeup between the two.
How would Picard treat Data at that point? Would there still be respect there or would Data become someone that Picard couldn’t trust as much?
What about Picard’s relationship with Thomas? Picard and Will were incredibly close, and perhaps his relationship with Thomas would be poor, giving Picard a battle on two fronts to deal with.
In the end, however, it was a smart move to not kill off Will. While the idea is exciting, it does shake up far too much of the status quo for fans to just accept. While Frakes wouldn’t have been out of work, his character’s friendship with Picard was a major factor in the show’s success. Doing anything to affect that chemistry would have been ill-advised.