The change that always intrigues me is that Frank Burns character.

In the original book and movie [he was played by Robert Duval] Frank is not an idiot. He's a competent surgeon. The reason the others hate him is that when a patient lives it's because Frank is a great doctor, and when a patient dies it's someone else's fault. Trapper punches him after Frank tells an 18 year old corpsman that the corpsman had killed a patient.

Winchester was overbearing and obnoxious, but he had a sense of humor and a modicum of self-awareness.