Hoi,
I understand why you used the pie notion however, Wikidata is more like a 3D ball [1]. A ball that is dense in places and more open in others. If there is one challenge that we have to face and where we will find no help elsewhere it is very much in the representation of our data in other languages.
Language diversity is in my opinion the hardest problem to tackle. Interconnecting to Wikipedia or to other sources is something that is well understood. It will become increasingly easy and obvious as we add more statements. The labels however.. there is not much help to be found. It exists in dictionaries but that is a route that is sadly closed for now.
Yes 2015 will be exciting.
Thanks,
GerardM