>>95341285Fred had several uses. He was a straight man sometimes, although Velma usually filled that role. He was the leader. Later he became funny when he was allowed to be aloof. He could figure out some clues, usually the more physical orienated ones.
Shaggy and Scooby were the real meat and potatoes of the show. They had all the best gags, got chased by monsters, and enough personality quarks to basically carry the entire show by themself.
Velma was the primary straight man, pointing out how silly Scooby and Shaggy were, she could be the smart one that pieced things together.
Daphne was given the boring lines that could have gone to anyone. She was the pretty one and sometimes got kidnapped.