The storage of #node in form and form_state in cache_form when using ajax comments.

I noticed a growing problem with ajax comments and the caching of it's form and form state in the cache_form table.

When viewing a node that has ajax comments turned on, 2 new rows get inserted in cache_form every time the page is refreshed.

I understand this is by design for ajax forms, but with node objects usually being quite large, on a medium traffic site, you can imagine how this table will grow in thousands of rows in a span of an hour. Resulting in very slow delete queries when cron is run per hour.

Is there an optimal way to make use of ajax comments in this manner?