As Phase 2 is progressing, we have to decide on how to represent data values.
I have created a draft for representing numbers and units, points in time, and locations, which can be found here:
https://meta.wikimedia.org/wiki/Wikidata/Development/Representing_values
including a first suggestion on the functionality of the UI which we would be aiming at eventually.
The draft is unfortunately far from perfect, and I would very welcome comments and discussion.
We probably will implement them in the following order: geolocation, date and time, numbers.
Cheers, Denny