Benjamin "Hawkeye" Pierce was MASH's true lead, but his best partner-in-crime wasn't Trapper John McIntyre, it was his replacement — BJ Hunnicutt. The groundbreaking medical dramedy ran for 11 seasons on CBS. Given how long it was on the air, it had a few cast changes over the years — most of them concentrated in its first few years. As an ensemble, losing characters left the show in a tricky position. Arguably the biggest departure from MASH, however, was when Wayne Rogers left the series. Considering how pivotal he was during the first few seasons of the show, his exit could have spelled the end of the dark sitcom.
https://screenrant.com/mash-hawkeye-trapper-not-best-partner-bj/