Lets first take a look at the cast

Not only do 3 of the characters have nothing resembling their normal cartoon clothes, but Fred's hair is pitch black, Daphne looks either fat or pregnant, and Velma is... god damn she's too hot. Fred's facial expression is... ****ing weird.
And then there's Shaggy. What the hell went wrong there? The casting seemed to be hit or miss: either they looked like the character, or they're completely wrong. It also looks as if they tried to cover it up by giving him the only clothes that resemble what the cartoon character had.

Seriously, I look like a better Shaggy.

Just throw some brown dye in my hair, and there you go. I could mimick the talk all the way to the crackling pubescent Zoinks, too. God this is horrible.
And Scooby, while would obviously have to be CGI, looks worse than the 2002 and 2004 movies. Its like they weren't even trying to cover up he would be fake.
Blah
Anyways