The DU Lounge

The show took a hit when Henry got killed. It was still good for several more years, and declined over time, especially in the last three seasons. Really, the prime was in the first four seasons before Larry Gelbart left.

Radar at the beginning was a cunning participant in whatever Hawkeye and BJ were up to; in the first season he would go into the Swamp and drink their moonshine. Then the show runners decided he needed to be naive and youthful, so he switched to grape Nehi and assumed an air of innocence. His character didn't grow; it changed based on the needs of the show.

Margaret was a joke until Loretta Swit negotiated a new contract, and she became a more sympathetic character. It's not like her character grew; her character changed. And so on.

Don't get me wrong; it's not like the show got terrible, not ever. But the end was a good deal less great than the beginning. It was a comedy and a good one; then they made it a dramedy and it was much less entertaining.