A Pup Named Scooby Doo made the characters have more dynamic personality quirks. For example, Fred was obsessed with the occult, mysteries, conspiracy theories and was a cartoon version of Manabyte.
So I can definitely see the appeal of A Pup Named Scooby Doo. Personally, the latest one currently on CN is the best one in a long time. It owns.
The appeal of Scooby Doo comes from not from the WHO DID IT aspect because it's usually obvious who did it, but HOW DID THEY COVER THEIR TRACKS?! which is half the fun.