Woulnd't it be better to have a set-up where all updates to the codebase of the English Wikipedia are (semi-)automatically propagated to all Wikipedias that use the same codebase? If not I fear that the non-English Wikipedias will keep on lagging behind on the bug fixes or new features such the enhanced recent changes page or subtle (or not so subtle) changes in the markup language, or whatever changes are yet to come. Making the updates automatic would also ensure that all future changes in the Wikipedia are internationalization aware, because if they're not the bug reports will start coming in from the non-English Wikpedias.
I'm inclined to think that if a particular community isn't large enough to come up with a developer to take care of its own needs, then it /should/ be left behind. UseMod wiki is a fine piece of software for a small level of activity, and if a group never outgrows it, I don't see any reason for me to waste time and effort on them. The German, Spanish, and Polish guys are on the ball and won't be a problem. But I don't plan to make much effort on behalf of the others unless they can come up with someone from among their own ranks with the energy and skills necessary to take care of themselves.