Laying into Toy Story is a bit like dissing the Beatles or picking holes in a Picasso painting. The Pixar series is an institution, a gilded saga that ushered in the modern era of CGI animation and introduced us to some of the most beloved characters of all time in the form of Tom Hanks’ rootin’ tootin’ cowboy Woody and his ever-expanding motley gang of plastic playmates. Without John Lasseter’s 1995 film we wouldn’t have The Incredibles, Wreck It Ralph or the Despicable Me films, Disney might still be putting out second-rate sequels to its classic hand-drawn fare, and Batman would exist only in live action form. It’s enough to make one shudder at the very thought.

And yet there’s something about the first full-length trailer for Toy Story 4, which dropped earlier this week, that makes me a little uneasy. Perhaps this is a deliberate ploy by the film-makers to shake up a franchise that’s now been going for the best part of a quarter of a century. Maybe it’s the way Pixar seems to have redesigned Andy (unless that’s Andy’s son?) so that he looks nothing like his youthful self in the earlier films. Perhaps it’s the notable absence of Ken and Barbie, by far the most vibrant toys from the last full-length instalment, 2010’s operatic Toy Story 3. (That toy with the handlebar moustache is not a hairy Ken, by the way, but rather Keanu Reeves’ Duke Caboom).

But mostly it’s the fact that the storyline here seems to be based around a moany spork named Forky who is apparently suffering from an existential crisis (after being transformed into a toy by Bonnie, the new owner of Andy’s erstwhile playthings). Doesn’t this seem like a creative decision from way left field? Perhaps all will become clear when we get to see the final movie and the Tony Hale-voiced Forky will end up as much loved as Woody, Buzz Lightyear and those cute little three-eyed aliens from Pizza Planet. But right now this seems like the new addition is only there to get Woody out of his comfort zone, and that this could easily be the moment the saga also gets a little lost.

Perhaps that’s why, elsewhere, the story seems to be retreading familiar territory, in a desperate attempt to get back on track. But do we really need to see another Toy Story movie in which Woody is tempted to leave behind his old life and venture into pastures new, a la his flirtation with the Roundup Gang in Toy Story 2? Must the villain of the piece really be a toy who seems innocuous at first, but ends up being evil and won’t let Woody leave – Christina Hendricks’s Gabby Gabby here; Lots-o-Huggin’ Bear in Toy Story 3?

Facebook Twitter Pinterest Ducky (Keegan-Michael Key) and Bunny (Jordan Peele) are among the new toys joining the motley gang of plastic playmates in Toy Story 4. Photograph: PIxar

Perhaps Pixar is making use of smoke and mirrors here: teasing us with what appear to be recycled tropes before hitting us with a tale so original that we wonder how we ever doubted them. Perhaps.

Intriguingly, Toy Story 4 was originally tipped to be a standalone sequel that would bid farewell to Woody, Buzz et al. But that was back when Lasseter was in line to return as director. Since then the Pixar creative head honcho has left the company he founded after being embroiled in a sexual harassment scandal, leaving Inside Out screenwriter Josh Cooley to pick up the reins.

That Pixar has gone back to basics with the fourth instalment is perhaps unsurprising, given the project’s difficult history. And the studio has turned round troubled projects in the past: the Oscar-winning Brave lost a director and went through radical story changes before finally emerging as a barnstorming medieval fantasy in 2012; The Good Dinosaur fell only just short of greatness after following a similar path to production in 2015. So there’s hope left yet that Toy Story isn’t jumping the spork this time around.