I would agree with that.
"8) Seven-Zark-Seven"
At least he was only at the beginning and end of each episode (for the most part.)
"7) "Dr. Sane"
I remember watching this show so much, but I remember so little of it. Guess I should look it up on Netflix.
"2) The Great Gazoo"
I liked him...and his accent too.
"1) Scrappy-Doo"
Definitely #1. And as for Scooby-Dumb - didn't Doo have a sister/cousin as well? The Scooby-Doo show ended up becoming the Patridge family with dogs.