In a regulated environment the compliance with development processes need to be proved. An organization needs to be able to access all artifacts for about 10-15 years depending on the regulation requ...
Last year sometime I created a SQL script which would do just this, essentially go through reviews meeting a certain criteria (date/age/status etc) and move any physical files to a networked backup location.
Removed this when I rebuilt the server with more storage and migrated to 64bit.
I'll try to dig out the scripts I used, nothing too complicated, but did the trick pretty well.
chances are however that this feature will be reinstated, especially, as you said, the review material is getting more and larger. I do think though, that certain types of review you may not want to keep the files hanging around as it would not make sense, so perhaps just archive certain types of files.