We have been having some success with embedding the Open Data catalog parts of a Hub site into a tab of our Ops Dashboard to enable easy direct data access. The Open Data parts of a Hub Site accept a variety of URL params to filter the dataset searches in a content library view, or to filter the displayed data of a dataset on a page of a particular dataset.
But a Hub Site itself - i.e., the initiative home page of a Hub Site and the child pages of that initiative home page - do not accept URL parameters that are then exposed or used by the content of the page. What if, for example, one could pass a URL param such as a user's name like this - http://myhub.hub.arcgis.com/?username=Jane and then by using the place holder {username} in a text card, such as "Welcome to our Hub site {username}" on the Hub site home page, the page could say "Welcome to our Hub site Jane!"
This trivial example is fine, but if any URL parameters passed in to the Hub site home page were available in this way to any of the widgets one can use in a layout, then the parameters could then be passed on to content embedded into the Hub site. If the operator dashboard passed a feature ID, and that feature ID were available in the Hub site, and the Hub site passed it as part of a URL param for an embedded scene viewer, for example, it would be possible to open a Hub page with an embedded scene that highlights a particular feature. It would help integrate Hub further into applications, and act as a general purpose web content glue system between Esri apps.
The options would be to maybe have a designated parameter that can be used for any sort of pass through, or to allow any parameters that are not already used internally to be passed through to the Hub site content... or to have a system like the Ops Dashboard where you explicitly define which URL params are accepted for the particular dashboard, and what they do / where they can be used.