When adding a URL, it would be really useful to be able to reference the value of an attribute on the current element.
Use Case: In PI AF an asset could have an attribute with the element path of its parent site. On a Pi Vision display of the asset, a link could then be added taking the user to the site. This would enable 'drill back up' after a user has drilled down. A display could then also contain 'breadcrumbs' showing the various ancestors.
Also see my post regarding substitution parameters on collection criteria.