10 'What Ifs' That Could Have Changed The Course Of Star Trek
Riker dead, Yar alive and what if Star Trek hadn't made it to season three?

Covering 800 installments and counting, Star Trek has chosen to tread a certain path through every incarnation and every behind the scenes decision. The Mirror and Kelvin universes have come to be and episodes have given viewers alternate glimpses of the future - and the present.
But what if things had gone differently? The possibilities on and off-screen are wild with creative choices, cancellations, and story paths all open to change. Some made it into the writer's room, a few even made it onto the screen only to be canned, and some branches are alive and kicking as part of the ever-growing book and fan film library.
While even changing one single piece would have made a difference, there are a few big ones it's well worth pondering. Fans are constantly querying what aligns as Prime or Kelvin, or what is canon and what isn't, yet there are some more fundamental considerations in the pot.
Star Trek could be unrecognisable (or non-existent) with just a few alterations and we can only speculate on how those would have twisted the frame of the franchise over the course of its expansive lifetime.
10. ...William Riker Was Replaced With Tom?

TNG's sixth season Second Chances pulls Will Riker's twin out of the shadows of Nervala IV. If we follow the expected cliche, the twin, Tom, should die at the end and the reset button hit. But here it didn't.
Instead, Will AND Tom survive which at least gives us DS9's great Defiant. If things had worked out differently though, we could have seen a very different final season and series of movies. At one point there was serious thought going into killing Will Riker and having his previously marooned twin take his place.
Well, not his exact place because Tom would have been sitting at Ops while Data got a promotion to first officer. For a series about to enter its seventh and final season, this was a bold move - and not the only one at the time. Descent very nearly saw the Enterprise moved to more sedate duties and crash.
The impact on the franchise from this move would have been galactic with no Captain Riker, no USS Titan move and that's just for starters when you consider the impact Will has had on the finales of not one but two of the new era of Star Trek.