More than 40 years after it began, Star Trek as we know it today is a vast and interconnected mythos, a saga of stories with generations of characters and their interwoven relationships, that together support and express particular attitudes (about the future, about storytelling, about what it means to be human) and a philosophy that Star Trek fans know and love, even if it harder to define than the consequences of a warp core breach. This is what makes Star Trek the planet’s shared story of a hopeful future, and partly why it has such devoted fans.
There are some apparent contradictions within this canon (which sometimes inspire very creative explanations) but the canon as a whole is solid enough to establish the shared Star Trek universe. Yet it wouldn’t take much for a feature film to shatter that universe. Just a few serious inconsistencies of character, story or attitude, and perhaps even of style, could separate this film from the rest of Star Trek. Which could also mean that if future Star Trek stories follow its pattern, the first 40 years of Star Trek will be a thing only of the past.
The danger is acute because familiar characters are no longer going to be played by the actors who created them and knew them completely. The presence of these actors who created the roles could largely overcome shifts or inconsistencies in storytelling (though not always, and certainly not for every fan.) Now there’s an extra step in believing in Captain Kirk: you have to believe in the new actor playing him, as well as in what he does.
Just the sight and sound of different actors playing Kirk, Spock and McCoy (however capable the new actors are) may be harder for many to accept than anyone anticipates. (Although New Voyages and other “fan” films have partly prepared the way.) The prospect of new actors playing these characters could be fueling some of the anxiety over canon.
But the biggest potential threat to canon is that the officials in charge of it are no longer the same. Until now, the Star Trek hierarchy was directly connected in one way or another to the founders, especially Gene Roddenberry. Even when his direct influence had lessened, he was always a presence to be reckoned with, and many in what became the Star Trek creative family had learned Star Trek directly from him.
But there’s a new Pope in town, and a new hierarchy, unconnected with the previous regime. Nobody knows what they’re going to do, but they are now in charge of the canon, and what they do becomes canon law.
So some fans are understandably anxious. This is really the first time that an official Trek story has been made so completely outside the original Trek family. (The exception of course is Leonard Nimoy. Even though officially he was only an actor in the film, his support and enthusiasm for the movie has probably gone a long way towards reassuring nervous fans.)