Think... BIGGER.

Jo has the right idea... Linked Data.

It sounds to me like the right way forward for domain specific interest data (like OSM) ...is,

Instead of 1 source of data (Wikidata)...and throwing domain specific interest data into Wikidata (not all data needs to live inside it).

Just use >1 source of data, i.e. Linked Data.

Wikidata does not have to be the 1 sole source... and besides, I am sure that eventually someone could just allow federated queries / joins to Linked Data.

Perhaps Wikidata can try to be and eventually help build... the 1 sole QUERY source for Linked Data. :) 

(Select OSM_ROADS contained_in "Ardennes")

Thad