Mr. Takamoto learned the art of illustration from fellow internees at the Manzanar internment camp during WWII, and went to work at Disney after the war. He worked as an assistant to Milt Kahl (who animated Pinocchio and Tigger among others) before joining Hanna-Barbera in the early 60's.
This piece by Neely Tucker in the Washington Post hits the right note, I think:
You had to be 8 years old, really, on your third bowl of Cap'n Crunch's Crunch Berries (your parents were still asleep, dreaming on a Saturday morning that you and your brother were already off at college), when the sugar rush was reaching your toenails, when the theme song came on in its complete and utter brilliance:
Scooby Dooby Doo, where are you?
Finally, I could find no evidence (other than having his name attached to the project as "creative producer") that Mr. Takamoto had anything to do with the abomination that was Scrappy Doo.