After three horrible shows (Or the Dark Ages as I call it) Hanna-Barbera attempted to rescue the series from ultimate destruction. The first attempt being this show FAILED.
I will agree that the premise for this show is great! It adds a sense of action and adventure that would later save the franchise. This show unlike it's predecessor relies more on adventure and spookiness then on humor. This time the ghosts are real!
The New Scooby-Doo Mysteries (Or the new Scooby and Scappy Show?) reintroduced the character of Daphne. This time Daphne had a new `80s look to her and no longer was danger prone (something else that would later save the series.) The addition of Vincent Price was very effective and added to the new mood Hanna-Barber wanted.
But with some many positive elements how did the show fail? Two names come up to mind: Scrappy-Doo and Flim Flam. If these two characters would not have been on the show it would have survived.
Scooby, Shaggy, Daphne, and Vincent alongside this new premise would have made for a terrific comeback. To bad Scrappy and Flim Flam had to ruin everything.