Unless I'm not understanding something, this would mean that a single koha installation could not be multilingual. This seems like the wrong direction IMO.
If that is the case it seems like a bad idea :-(
Another thing to consider is that it makes it more difficult to customize a template. It's easy enough to figure out what's going on with the markup if the text is there in the page, but it's different when everything is '<TMPL_VAR NAME="STRING_LoggedInAs">'. It also means that if you go in to make changes to your template, you've got a dilemma between simply entering the text as is, or going to the master language file, defining a new text variable, and inserting that variable delclaration into the page. It's not a problem if the template is on a one-way trip to your site, but if you want to later share it with others you have to be careful of all those changes. All that is not to say I don't think the idea has merits... I just think it needs to be thought out. -- Owen