In Special:MergeHistory , it would be useful to have an option to call for a list of the edits of the destination, letting the user mark "first edit which is to be kept": edits before that would be deleted. Those unwanted edits would be redirects and miscellanea that were already at the destination page name before the cut-and-paste event that caused need for the history-merge.

After obeying that, the list of movable source edits would have to be updated and re-displayed.