I don't think I understand your suggestion. This is the TemplateData for the English Wikipedia's "citation needed" template:
<templatedata>
{
"description": "The template is used to identify claims in articles, particularly if questionable, that need a citation to a reliable source.",
"params": {
"date": {
"label": "Month and year",
"description": "Provides the month and year of the citation request; e.g., 'January 2013', but not 'jan13'",
"type": "string",
"autovalue": "{{subst:CURRENTMONTHNAME}} {{subst:CURRENTYEAR}}",
"suggested": true
},
"reason": {
"label": "Reason for citation",
"description": "A reason as to why, or for what content, the citation is needed; use single quotes, if any",
"type": "string"
}
}
}
</templatedata>
No editor or reader at any article ever sees that. I don't think it makes any sense to add a Wikidata link to the TemplateData.
Are you looking for a sort of magic infobox, so that you can type {{infobox}}
and Wikidata fills in all the fields for you? That already exists, and it has nothing to do with TemplateData. Have a look at w:es:Jimmy Wales for an example of a long infobox that is mostly pulled from Wikidata.