A central repository that will contain all data that are language-independent.
Create a central repository that will contain all data that are language-independent, with a special emphasis about data that change more often. Examples: census data about towns and countries, statistics about population and other things, names of current presidents and mayors, results of elections, etc.
Create some system to use these data on all wikis in an automatic way, so that when a new president is elected in a country, we simply change the name on the repository and all wikis will see it without having to change it manually.
On small wikies in particular, it's really difficult to keep data updated, and very often these wikies show wrong or old informations. Big wikies can cope enough well with this issue, but anyway this proposal will save a lot of time and will guarantee a higher degree of accuracy, avoiding possible inconsistencies between different wikies and reducing delays in the updating of data.
This system will also provide an automatic conversion between different units of measurement (example: the data will be stored in kilometers but delivered in miles to wikies that prefer this unit).
Technically I think it's feasible. The work of: 1) establishing the central repository, and 2) "distributing" data to all the wikies, can be automatized with a bot. Obviously it will not be very easy, given the huge amount of data that Wikipedia contains.