1 It should be possible to control the number of items included in a feed independently of the number of items included on the page (the latter, however, possibly setting an upper limit). This would be particularly useful on archive pages providing a feed. Presently the feed grows huge, if the archive page has no limit on the entries listed on it (as in the list of [all entries][ionfaq] in the Ion FAQ). An alternative useful filter would be filtering by the age of the page.
3 [ionfaq]: http://iki.fi/tuomov/ion/faq/entries.html