Add events that use calculations to read & write (get & set) all settings in all worksheet and dashboard dialogs.
I don't know exactly how, but I picture events available in e.g. axis, reference lines, field sorting, and quick filters working together with calculations, that have read & write access to various settings. I think about something similar to events in Microsoft Access, except much simpler.
It could be a powerful alternative to various ideas about dynamic this and dynamic that, such as, dynamic axis titles, dynamic column aliases, dynamic sorting, dynamic reference lines, dynamic min/max axis, dynamic start/end of date axis, and so the list goes on, until every setting in Tableau is dynamic. This could be a powerful alternative that solves everything at once.
... and probably 100+ more ideas requesting similar things that could be done if we had dynamic settings of settings.