Being forever ditzy is supposed to be a good thing on this show. Characters rarely ever wised up. Barn was frequently ditz, so are all the Darlings, Ernest T., Gomer, Goober even Aunt Bea, and Warren as well. About Warren, the writers gave him harrassing stupidity and he really seemed to tick Andy off with his dumbbell lawman ways (remember the ep when the prisoners under Warren's guard still had cash on them). I really feel we are supposed to think Andy soon axed Warren from the Sheriff's office.

I never liked the Warren episodes.

Warren wasn't used properly, IMO. They shouldn't have tried to make him a Barney clone.