Hi David
Agree it's total scope creep - but echoing samdds - the need to update more fields via csv is great...
http://drupal.org/node/422282 - Update existing nodes on import - gives you an idea of the demand...comment #110 is a good summary - you get a mention too!
My usage would be to update my free-tags - for example, tagging a set of products as "sale item" or "10% off" - at the moment it has to be done by hand which takes ages.
Another use would be where you make a mistake and have to change the category of 300 products by hand - but lets not go back there!!! - using a stock & price updater methodology would be brilliant for that...
If you don't ask and all that!
Cheers
James