Cinema has not always been as conservative a form of media as it seems in 2017. Prior to the era of pay TV, multiplexes were, if not exactly an uncensored domain, certainly a racier place than one’s front room on an average evening, pre-watershed. But somewhere along the way, TV got Orange Is the New Black and Game of Thrones, and the big screen was left languishing in its wake.

The need to flourish in international marketplaces has played its part. While US and UK audiences might be largely fine with queer superheroes and gay Jedi knights, censors in countries such as China and Russia would almost certainly not be. Hence, studios have tended to veer on the side of caution. There was a great deal of fuss earlier this year when it was revealed that the Yellow Ranger in the latest big screen version of Power Rangers was set to become Hollywood’s first queer superhero. In the end, a creative decision that was flagged up as a game-changing moment in cinematic history ending up looking pretty weak.

If change really is coming, it’s certainly taking its own sweet time to get here. Recently, Thor: Ragnarok’s Tessa Thompson was moved to share her queer interpretation of Marvel’s Valkyrie, a key player in the superhero mega-saga’s latest instalment, on Twitter. But despite Thompson apparently persuading director Taika Waititi to shoot footage showing a woman leaving the cosmic superhero’s bedchambers, just to make sure no one was left in any doubt about her character’s sexual preferences, the scene did not make it into the final cut.

She’s bi. And yes, she cares very little about what men think of her. What a joy to play! https://t.co/d0LZKTHCfL — Tessa Thompson (@TessaThompson_x) October 21, 2017

YES! Val is Bi in the comics & I was faithful to that in her depiction. But her sexuality isn’t explicitly addressed in Thor: Ragnarok. https://t.co/hmb5lYN5to — Tessa Thompson (@TessaThompson_x) October 23, 2017

Marvel parent company Disney can hardly be accused of homophobia – the studio was more than happy to publicise the high-profile inclusion of a gay character in children’s movie Beauty and the Beast earlier this year. But given geek culture’s generally queer-friendly disposition, it does seem strange that the studio failed to grasp the opportunity handed to it on a plate by Thompson. The move would also have played wonderfully with all those highly vocal backers of the recent “give Captain America a boyfriend” social media campaign.

Perhaps Hollywood has been put off such high-profile sexuality switcheroos after the Star Trek Beyond debacle, which saw the film’s makers retooling John Cho’s version of Enterprise helmsman Sulu as openly gay, only to see the role’s originator, George Takei, label the decision – which was made in tribute to Takei’s own tireless gay rights activism – “unfortunate”. Or maybe Ragnarok’s 130-minute running time couldn’t possibly handle an additional 10 seconds to make what would have been a pretty powerful point.

Marvel is doing its best for diversity in other media. The comics have featured gay or queer characters such as Mystique, Iceman and Northstar for many years, while Netflix’s Defenders shows have the inimitable Carrie-Anne Moss as lesbian lawyer Jeri Hogarth. So maybe the studio doesn’t see any current need for explicitly queer characters on the big screen. Or perhaps there are still concerns about how international censors might react: the authorities in Malaysia were not keen on Disney’s gay subplot in Beauty and the Beast, though the studio, to its credit, did stand firm and refuse to cut any scenes.

Josh Gad and Luke Evans in Beauty and the Beast. Photograph: Moviestore/Rex/Shutterstock

There is an argument here that a softly-softly approach makes sense for other reasons. Romance certainly plays its part in the Marvel universe, Chris Hemsworth’s Thor was once rather attached to Natalie Portman’s Jane Foster, while the surprisingly touching relationship between Scarlett Johansson’s Black Widow and Mark Ruffalo’s The Hulk was deftly handled by Joss Whedon in Avengers: Age of Ultron. But given superhero flicks are essentially action-fantasy movies, they might become rather unbalanced by any overt move to suddenly flag up love affairs of any persuasion.

On the other hand, this surely means gay characters might easily be introduced without changing essential dynamics. Altering Tony Stark’s sexuality might cause something of a hullabaloo, but it would hardly have the same effect on storylines that shifting 007 to a preference for male lovers might have on James Bond. Warner Bros’s DC extended universe might easily have included a scene nodding to Wonder Woman’s queer identity in its warm-hearted superhero origins story – though, once again, it ultimately chose not to.

When Marvel or DC does finally choose to push the envelope, it’s important the studio does so in organic fashion. An example here would be the forthcoming sequels to JK Rowling’s Fantastic Beasts and Where to Find Them, which will feature Jude Law as the young Dumbledore. Rowling has made it clear that Hogwarts’ future headmaster was passionately in love with his eventual enemy, the dark wizard Gellert Grindelwald (Johnny Depp on screen), and it would be disappointing if that enticing dynamic was written out of the forthcoming movies. Likewise, if Marvel brings back Thompson’s Valkyrie for future episodes, it would be nice to think the studio might decide to be a little braver next time around.

There are other options, however, hidden in Thor: Ragnarok’s DNA. As Wired pointed out recently, Loki has had his fair share of same-sex relationships in the comics, while one of Waititi’s breakout characters, the relentlessly cheerful Kiwi-toned rock monster Korg, has also been identified as gay. Either would make a fine choice for Marvel’s first queer superhero. It does seem a matter of when, not if, superhero movies finally take the plunge.