I have a use case for being able to dynamically generate text in text boxes that has been created by users. You can achieve this by using parameters as per this blog but this is a complicated way to do it.

This idea is to be able to insert measures and attributes directly from the subject areas and datasets directly into the text editor in the same way as you do in the expression editor. This would mean that authors can create a text that changes as users select filters. This would need to work for core dataset items and custom calculations.