If octopus could scan packages for variables from Web.config, app.config and xxxDeploy.ps1, looking for appsettings and connectionstrings and $OctopusParameters[]. Then when adding variables it could suggest variable names. But also when creating a release it could warn about new settings/variables that have been added since last release and for which there was no variable?

Maybe it would actually be octopack that scanned for variable names and provided it as metadata in the nuget spec?