When Mash began in 1972 it was just another sitcom. And thus it was very sitcom-like. Over time it became more realistic (looking). By the end it had practically broken all conventional tv standards and was nearly reality itself. But it was slightly less enjoyable so realistic (looking).

I think not.

Though MASH was a sitcom, I always thought that in the beginning seasons they made valid social commentaries without being preachy. In a word, the humor was most important, but the framework was structured around people who seriously cared.

In the later years with BJ, the bite was lost and the drama took foreground. Though there were the pranks and the putdowns and such, it was never the same. Eventually it became way too serious, not necessarily that the show was bad, but that it seemed less and less to resemble a sitcom.