Hi Michael,
(I cannot speak on behalf of WMF, this is not official)
The plans for Wikidata are to carefully attribute sources of data,
which comes much closer to what you need, i.e. 3rd party data are
separatable. For the start the CC0 license has been chosen which gives
you unlimited re-use rights, but other licenses may be supported later
if needed. The discussion was to decide this only when the use cases
start to come in.
The real data use is still to come, so far wikidata can really only do
the interlanguage linking of wikipedia pages. The rest is being worked
on right now.
Best
Gregor