GnuCash supports the ability to export your entire account
tree structure so that you can (presumably) import it into
a new finance database. It would be nice to add an option
to the File menu that would allow you to export not only the
account structure, but also (1) The balances of all Equity,
Asset, and Liability accounts as of a certain date and
(2) Any transactions for any type of account that might
exist after that given date.

My motivation in requesting this feature is that it would be
very convenient to be able to (at the start of a new year) to
be able to start a new working set of accounts without having
to re-enter your current financial state.

I also believe that this feature would also improve load times
for people who have been using GnuCash extensively for extended
periods of time. This is definitely not a high priority item,
but a nice-to-have.