MASH was a show that grew and changed with the times. Based on the outrageously funny movie of the same name, the show began as a real continuation of its big screen basis; filled with the slap stick antics of Hawkeye and Trapper John as they fought the establishment and tried to stay sane. Those first shows bear only a passing resemblance to the insightful, sensitive but still witty shows that came towards the end of the series. Clearly more than the sum of its parts, MASH was special and any sequel would have to be too.
"After MASH" could have been a good continuation of MASH's legacy but came too soon after the original went off the air. Moreover, the ensamble cast that MASH had built up and fleshed out over the years was almost totaly stripped away and only three characters managed to make it to the sequel. Without any of the old favorites on board, and none of the counter culture humor that MASH was built upon, After MASH died quickly.
Frankly, I don't think the show was a real stinker in its own right so I won't slam it. I think the shows I saw were all good enough, but they did fail to measure up to the originals. In a time when the original series was still very fresh in everyone's minds, and still regularly being viewed in syndication, anything less worthy with the MASH name attached to it was doomed to failure.
Would I like to see a MASH reunion? Yes, as a one time reunion featuring all of the characters as they have aged, but not as a series. The original was good enough so I don't think we can or need to go back.