Prior to his work on The Guardians of the Galaxy, filmmaker James Gunn mostly served as a screenwriter for a variety of films, including the 2002 Scooby-Doo movie. Years ago he revealed that he had intended to make the live-action Scooby film "edgier," and that the first cut was rated R by the MPAA. At the same time he expressed his belief Velma was gay, and now he's outright said that the studio behind the film, Warner Bros., rejected the idea to depict her as gay in the film.
When a fan asked him on Twitter to make another live-action Scooby Doo with Velma as a lesbian, he replied, "I tried! In 2001 Velma was explicitly gay in my initial script."
By now it's evident that the film went through significant changes during production, so much so that the studio insisted on digitally reducing the cleavage of actresses during post-production. "The studio just kept watering it down & watering it down, becoming ambiguous (the version shot), then nothing (the released version), & finally having a boyfriend (the sequel)."
He also replied to more fans asking about the "ambiguously gay Velma" depiction that was initially filmed for the original, adding that a lot of the hints towards Velma's sexuality were actually filmed. He wrote that "you can see some of it in the deleted scene[s]," and that his first draft featured a scene in which she "serenades Daphne," and later kisses her. "Both of these were shot," he noted, "all easily available, known information, just as everyone knows the movie was initially rated R by the MPAA."
Gunn has been busy working on post-production for The Suicide Squad, and pre-production for The Guardians of the Galaxy Vol. 3, so it seems unlikely that he'll return to the world of Scooby-Doo anytime soon. If he does, however, expect Velma to to be depicted closer to how he originally intended. When one fan suggested he film a third entry with the original cast, he joked, "That would be one incredibly long life-span for a Great Dane."