Use Time Ranges in formulas: Make the Time Range a named member in the Time Dimension

If  Time Ranges were  true named member in the TIME dimensions we could easily control  formulas and filters based on a time range.  It would also allow for YoY changes in formulas to be maintained easily w/o having to create multiple line items.  Many companies need to save off older versions for compliance reasons.  Adding the ability to keep old formulas and control how they work accross time would be easily done if we could use time range names.