What I love in English Wikipedia are lists like this. It is more than likely that for every Tanzanian region there will be a similar list and as a consequence we can include all these fine politicians to Wikidata, list them in whatever Wikipedia.
As more politicians for Tanzania or any other African country are added, politicians will pop up who have held multiple offices. This will be explicit in Wikidata and in Wikipedia you could use Special:WhatLinksHere.
Technically there is not much stopping us from associating red links with Wikidata items. This is the same guy used in the "WhatLinksHere" and you find him in this list that is a work in progress as well.
Think this through.. With lists like this in any Wikipedia, these people are findable, linkable. It will be possible to state in text what a given commissioner did and, there will be no ambiguity because of the link.
So I love English Wikipedia for the rich resource of information it is. I love its editors who provide us with the information that enables the reuse of data. I will rejoice when it is recognised that we can do much more. When we accept that together, as an ecosystem, we are in a position where we actually share the sum of all knowledge that is available to us.