Replacing Identical/X templates
I'm all for "similar messages". Should of course be based on the English source message, not on existing translations.
I like your suggestions. For your first option of using a good search, would the results be displayed on a normal 'search results' page, with the page title and some of the page text printed? This would be useful in searching for a particular word or phrase, if we could search in the English language messages only, or in English plus xxx language only. Or I could search for the English word (or phrase) or translated word in the xxx language messages only, on a separate tab. Or were you thinking of having a layout for search results that was like the translation tool layout? That would be brilliant. Could it search in both of all the English source messages and all the xxx language messages at the same time? That would save a lot of time doing searches using my browser 'find' tool.
'Search for similar messages' should also be useful. Even if it doesn't quite do all that the current manual system could do, it's a price worth paying to eliminate the time to create and maintain the manual templates.
I forgot to mention in my previous post that one of the uses for searching for a particular word is to check that a particular xxx language term isn't already in use to translate a particular English term, so as not to have one xxx language term being used for two different English terms.