The Klingons you know from Star Trek were going to be much different.
If you grew up a fan of Star Trek: The Next Generation, no doubt you got to see some very fun and unique stories about the aliens of the franchise. As the sequel series of sorts to the first Star Trek, commonly referred to as The Original Series (or TOS), The Next Generation gave fans the opportunity to learn more about Trek lore among some of the most common aliens. One alien race, The Klingons, was not only set to be radically different in the sequel series but the sequel series itself was planned for nine years prior.
Often forgotten to time was a Trek show in production dubbed “Phase II”, and it was going to be a sequel series to the original. Long story short, the network the series would’ve debuted on ended up not happening and the show was changed into Star Trek: The Motion Picture.
But what about those Klingons, you say?
Star Trek would’ve had vastly different Klingons.
The idea for the Klingons in Star Trek: Phase II would’ve been more akin to the Vulcans and Romulans, only more close. In a completed script, called “Kitumba”, the Klingons would be a caste of an alien race and not the entire race. Serving as more of the military/hunter side of society.
A fan series did their own version of Kitumba, and depicted the warrior Klingons as the type fans have known since The Next Generation, while the other caste were depicted as the original type of Klingon from The Original Series.
This may have been the direction Phase II had gone in with their Klingon’s, as the movie franchise was the first to really display the Klingon in a different manner than we were originally accustomed to.