When Gene Roddenberry, the creator of the Star Trek franchise, passed away in 1991, the direction of the series changed - and not in any small way, either.
See, Roddenberry had a very clear idea of what he wanted Star Trek to be. At its heart, his vision of the future was an absolute utopia, a world free of greed, famine, poverty or prejudice. And, indeed, this is reflected nicely in the Original Series and the early seasons of The Next Generation. That's not to say those ideas were coldly binned after Roddenberry withdrew from his consulting role, but in bending the 'rules' just that right amount, the writers were now free to dial their sci-fi creativity up to Warp 11.
The result? Star Trek: Deep Space Nine, a series more daring and multifaceted than any of its kind that had come before it.
With its more varied cast, darker themes and unique setting, Deep Space Nine was a momentous leap forward for the franchise, and with its changes to the Star Trek formula came many series after it, carrying on the broader vision of the future it had ushered in. Here are these very changes.
10. Adopting Characters From Past Series
Admittedly, since The Original Series and The Next Generation are set a century apart, it would be hard for them to share any main cast members (despite many of the original crew still being alive by this point). This is not the case with TNG and Deep Space Nine, which run parallel to each other starting from TNG's sixth season.
As such, it's easy to see why the writers chose to relocate some of TNG's characters over to Deep Space Nine. The first example is Miles O'Brien, a humble transporter operator on the Enterprise-D who is, at best, a minor supporting character on the show. As a main character on DS9, O'Brien is promoted to Chief of Operations, and we get to see some intriguing new sides to his rich, down-to-earth personality.
Another recurring character, Ro Laren, was also intended to be part of the show, but when actress Michelle Forbes turned down the offer, the role was repurposed as Major Kira Nerys.
But what makes up for this is that Lt. Commander Worf, the Klingon fan favourite from TNG, comes to the station in the fourth season, staying for the remainder of the series. In this new environment, it's refreshing to see more of these old faces that still have a lot to give.