Most sites will have files on the file cache that are referenced on different parts of a site (e.g. JavaScript files that slightly alter default outputs on a page, XSLT transforms etc.). Sometimes you might have to make changes to those files but not go-live with them straight away to give the customer the chance to review it or more importantly have the option to go back to a previous version in case something goes wrong. Internal staff is generally careful with this sort of thing and we commit files to svn etc. however mistakes do happen, it's not guaranteed that you will always have the latest version of the code committed(e.g. customers might change change those files themselves and not tell us) therefore file versioning would be very useful.
Thank you for your feedback, it's a very good suggestion although we might implement it in a slightly different way.
We are looking at the possibility of having additional version tracked files for things such as JavaScript etc.
We are likely to leave the file cache "as-is" for backwards compatibility more than anything else.
I completely agree. The way our sites work means a lot of customers have Java script on them and not having a version track or the ability to have these in preview mode and not put it live straight away is a real problem. I think almost all of our sites have java script. Please can we do this!