Hey,
Why do you want to keep interwikis in the article? I think you could directly drop langlinks table if interwikis are managed by wikidata.
Usage of Wikidata is optional. Initially it will only be used where turned on. And people will be able to override "language links" locally.
Cheers
-- Jeroen De Dauw http://www.bn2vs.com Don't panic. Don't be evil. --