Problem: TemplateData is an important tool for making editing easier for newcomers. However, because it doesn't allow wikilinks and other formatting in the template description and parameter descriptions, its usefulness is limited in VisualEditor. It also makes it insufficient to suffice for template documentation pages, meaning that many have to have a largely redundant "parameters" section in addition to their TemplateData section. en:Template:Format TemplateData, a crude workaround, has numerous flaws.
Proposed solution: Build functionality into TemplateData to enable wikilinks and other basic formatting.