I believe an archiving system would be very useful, however I don't feel that it should be prioritized if it interferes with more important upcoming improvements.
For me, I use an archive tag to organize data, however, when it comes to removing it from search I would need to search with -tag:Archive.
The solution I am using now, like CalS mentioned, is moving archived data to another Evernote account every year to remove the notes from search, and share the notebooks back to my main account so I can access them. I still have an archive tag (and notebook stack) so I don't need to go through the notes for what I need to move to a different account.
This is working for me, however, a dedicated feature for this would be appreciated.