I’ve always wondered why Star Trek: Deep Space Nine abandoned their plans for Thomas Riker, the treacherous transporter clone of Star Trek: The Next Generation‘s Commander William T. Riker (Jonathan Frakes). Thomas Riker was first introduced in TNG season 6, episode 24, “Second Chances”, in which he is discovered living in isolation on Nervala IV. This forced to Thomas to see the man that he eventually became, and he found that Will Riker didn’t live up to expectations. Thomas was appalled by Riker’s rejection of promotion, and left the Enterprise to serve aboard the USS Ghandi as a Lieutenant.
https://screenrant.com/star-trek-ds9-i-wonder-why-riker-clone-plan-abandoned/