Wikidata could provide the most value particularly to the big Wikipedias by replacing the current red links. Red links are really simple. When an article exists, it will link it and that is exactly where things go wrong; when an article is added for a homonym, you need disambiguation. This is where Wikidata makes a difference.
Wikidata is ready because it includes all the articles of all Wikipedias and thereby its capacity to disambiguate is superior. Moving existing red links to Wikidata items may be automated because articles in other languages may have that link already. New red links in articles are checked for a need for disambiguation and when there is no need, a new Wikidata item is created.
In the Reasonator the concept cloud shows links as used in Wikipedia articles. Typically these links could exist as statements on the item. For Mr Ormel, a Dutch psychiatrist, there is only one article so it is not a complicated example. In the text there is (now) a red link to Mr Frank Verhulst. There is now an item for Mr Verhulst and as people convert red links, the statements on the item may be reflected in a tool like the concept cloud.
Another benefit is that links can be verified by tools like Kian. When a subject is about psychiatry for instance, a link to a person who was a football professional all his life is likely wrong and in need for disambiguation.
Arguably changing the red links in Wikipedia can be easily enhanced using information from Wikidata. It will improve quality in a meaningful and measurable way. Many of the functional parts already exist and it is therefore mainly a task of cobbling things together.