Now lets review a cartoon that has a lot of criticism for going way off formula. Lets look at Shaggy & Scooby Doo: Get a Clue.

But first some history, when it comes to Scooby Doo, arguably the best selling characters are Scooby and Shaggy, that's why they could get away with their own series along with Scrappy Doo, which went off formula from the ghost chasing to genuine mystery solving, something that also existed with the TV movies, but this incarnation Get a Clue took things in such a different direction that it's completely lost as Get a Clue has less to do with mystery solving and more to do with taking down an evil genius mad man. The plot goes that Shaggy's rich uncle Albert goes missing and leaves everything to Shaggy in his will but the evil Dr Phineus Phibes is after Albert's research so it's up to Shaggy and Scooby to stop him, using all forms of technology open to them. This is one of the last cartoons made by Joseph Barbera before his death at the impressive age of 95 years, Joseph of course being one half of Hanna Barbera.
My history with Scooby Doo is a bit mixed as I appreciate the originals and even some of the Scrappy Doo series, I'm not such a fan of the modern Scooby Doo shows or it's TV Films, as for this one it kind of falls in between which is strange considering that it doesn't have anything to do with solving mysteries, in fact you could say it's a poor mans spy and super hero show. But in a strange way I welcome the direction this series was taking.
There's a point in history where a character in any cartoon becomes tired and Scooby Doo and his friends at this point were becoming this and Get a Clue was the breath of fresh air it needed, even if it took away what Scooby Doo was famous for, it's no different to the many spinoffs during Hanna Barbera's run during the 70s and 80s which looking back was utterly, utterly terrible.
So in conclusion I'd say this made people stand up and notice and while fans would clearly miss the traditional Scooby Doo, it doesn't hurt to test the waters of another genre.