I would recommend going with the i18n-foo packages and trying to keep the koffice and kde stuff merged and synced. This way, someone can fetch and install the language they want without needing to install ALL languages. And the merging would at least cut the number of different packages in half.
I realise this would mean many more packages than just using a single i18n package for all languages, but the single package is quite large. If I want Irish language support on my daughters system, I don't necessarily want to install french, german, and several versions of japanese and chinese as well. I know that I've seen these broken down into seperate languages on the kde site before, but that could have been jsut that particular time I checked. I agree that this should be taken up-stream to ask KDE to keep the languages seperate and merge koffice and kde together. Of course, this is just my opinion and my reasoning behind it. Cheers, John Gay