So now that the film is out...woof. (Not in a good way)
To preface, growing up Scooby-Doo was certainly one of my favorite series. It's certainly had it's ups and downs through many variations, but all in all there's some huge nostalgia here.
This film is a unfortunate misfire, as it's far more a superhero film/introduction to a expanded universe than a Scooby-Doo film. With the exception of Scooby and Shaggy, the rest of the gang are barely in it. To be fair, something like that isn't out of the norm for this series, but when it was initially announced as Scooby Doo origin/regular S.D. film, yeah it's a slight. An like with many recent films that try to kick off a expanded universe, they fall into the same pitfalls as the others.
The story is both convoluted-yet-cliched which I'll admit it's a feat in itself. The animation is fine, the voice acting is hit or miss. I really didn't care for the celebs doing the Scooby Gang, though with a couple other characters I was fine with. I actually liked Ken Jeong as Dynomutt and Tracey Morgan as [REDACTED], they were probably my favorite characters in the whole thing.
Then there's the humor/writing...hooooooooooooooo BOY. There's a ton of topical references, and there's a good chunk of stuff that's already dated. I'm still stunned they make one reference to someone who hasn't been relevant in a while, and then they keep referencing them over and over like they're proud of it. There's also a ton of H.B. references as well, though for me it felt like a lot of pandering with the way everything was.
All in all, while I've personally seen way worse out there, the film is still a miss for me. They could've had something neat, but they slipped on the execution. Ultimately, I'd rather have gotten a straight-up Scooby Doo! film, but that's not what they made. If they still wanted to put in H.B. refs/characters, they could've done something along the lines of the Mystery Incorporated series which did do that, and pretty dang well I might add.