Ethnic Scrappy: Joe Jitsu and Go-Go Gomez were drawn just about as stereotypically as you might imagine. Gomez could move very fast, although he did so with lots of "Arriba! Arriba! Yeeha! Yeeha!" yells that turned him into a human Speedy Gonzales. (Mel Blanc actually voiced Gomez in the Mr. Magoo cartoon in which he appeared).
Executive producer Henry Saperstein would comment that Joe Jitsu was created as a good guy to help soothe any ill feeling to the Japanese after the end of World War II.
Fair for Its Day: Joe and Gomez may be ethnic stereotypes, but they're also intelligent and capable heroes, as opposed to Hemlock and Heap, who tend to solve their cases through dumb luck more than anything else.