Feature summary (what you would like to be able to do and where):
This would be similar to preloadparams[]= with the difference, that additional input fields are shown (might be related to T382679, but instead of loading a whole editor, a MediaWiki-extensions-TemplateWizard would suffice) . These would—contrary to preloadparams[]= not be send as numerically-index URL query parameters but as named ones

When TemplateData is installed, the inputs could differ based on the parameter properties and additional validation could be provided (T382682)

Use case(s) (list the steps that you performed to discover that problem, and describe the actual underlying problem which you want to solve. Do not describe only a solution):

Benefits (why should this be implemented?):
When combined with T194606, workflows could be improved