Duplication checks in aggregator are naive and incorrect

In the RSS 2.0 "specification", a GUID is an optional element that is meant to "uniquely [identify] the item" of that particular feed. In Drupal, however, we're going too many steps further: if a GUID doesn't exist, Drupal treats the LINK of an item as a unique value. This is incorrect: it assumes that the LINK is unique, which no version of RSS has ever indicated as being true: in many non-blogging feeds (such as a weather feed, where I am unable to get the second ITEM), multiple bits of information are spit, all with the same LINK. Drupal, however, only sees one of those items, because it erroneously treats the LINK as if it were unique. Drupal should check only for GUID, and then a direct TITLE + LINK + DESCRIPTION check for each item - only then should something be considered unique. (So yes, minor spelling errors would be considered a new unique item - some readers even go so far as to show a diff between two items that have met a threshold of similarity).