The DU Lounge

Only Harry Morgan as Colonel Potter was a good replacement IMO though his casting significantly changed the tone of the show. But he was such a good actor to me I could accept him in that role. I like and respect Mike Farrell, but his character of BJ couldn't hold a candle to Trapper. David Ogden Stiers was a great actor, but his character was all wrong for the show. As horrible a person as the character of Frank Burns was, he added a lot to the dynamic of the show though I understand why Larry Linville chose to leave the show. They were probably smart in not replacing Gary Burghoff with a new actor, but he was crucial to the show, and the show declined precipitously after he left (even if the rest of the cast hated him as is rumored). The changing of Klinger's character was absolutely terrible to me.

The last several seasons are completely unwatchable to me. This blogger nails it for me:
https://manofwow.blogspot.com/2015/06/the-slow-burn-of-mash-jumping-shark.html

I can watch any episode from the first 3 seasons at any time. The next couple seasons after that are OK - watchable if I'm in the mood. If a Post Frank Burns episode come on, I'll generally change the channel (probably quickly). If an episode comes on from when after Radar left, I'll run screaming the other direction.

As much as I love Alan Alda and the general underlying politics of the show, as it went on, Alda had more control over everything and seemed to either forget or ignore what made the show so likeable in the beginning. M*A*S*H was much better as a comedy with dramatic elements than the other way around.