It would be extremely useful to have functionality similar to TestPage.SetValue, except attached to CurrPage. This is similar in concept to https://experience.dynamics.com/ideas/idea/?ideaid=8aa70fdb-2b67-e911-b047-0003ff688f4c except that the solution there was to require explicit opt-in by the developer of the page. These fields are exposed for end users to edit, so it doesn't make much sense that you can't edit them in AL. Specifically, this would allow an extension to set fields for which the source expression is a variable, without opening up direct access to the underlying variable.

Just as an example use case, I don't believe that it is currently possible to modify the out-of-the-box Copy Job page to mark the "Copy Job Prices" value by default.