There is an RSS feed which informs me when a page in a space is updated. It tells me which page was updated, but not by whom, when, or what.

Here I think especially what was changed is interesting. Therefore I'd suggest that the feed item descriptions should be the accumulated diff since the previous revision published through the feed. This is how it works with JSPWiki. Also that would make the feed much smaller in size. Currently it's over 40KB.