Yes, those sound like familiar reasons for wanting to rename a user attribute. If one is formalizing as one goes along, then renaming may be more common than if one knows it is critical to do a lot of planning at the outset.
I been happily assuming that renaming a user attribute in Tinderbox involved editing the box in the inspector. I've gotten away with that a couple of times without losing data.
That assumption seemed natural because that is similar to how one changes a "field" name in databases that are known to require more structure up-front, among them Microsoft Access on Windows and Tap Forms on the Mac (probably FileMaker too, though I no longer have a working copy). Changing a column header in a spreadsheet or in an app like OmniOutliner is also straightforward. (I say straightforward for the user, not necessarily the developer!)
It's good to know the safe workaround of copying the values to a new attribute, and deleting the old attribute, though it made me think of what one had to do in dBASE under DOS, back in the day.