I've recently completed some work on the search index. Checkout our search page on this site and see what you think. This site is running the latest build and has the new search features.
We are now showing the author, created and modified dates in the search results and you can filter on the last modified date with date pickers to narrow in on time. The showing and hiding of those things is configurable.
Note that I didn't end up sorting by date because search needs to sort by the matching logic and the strength of the match. There is a way to sort by fields in lucene but it is very expensive in terms of memory usage because to sort it has to cache an array of the value of that field for every document in the search index. So it would get more expensive the larger the search index gets. Basically it isn't what lucene is optimized for and I decided to stick with its strengths.
I'm also working on some new experimental features that leverage the search index. Basically I can query the search index for the content by created or modified date so I'm creating a "Recent Content" feature that can list and link to things in a feature agnostic way so long as the feature implements search. It will have a setting for filtering it by feature and a few other settings. I've also created an rss feed that can return the same data if enabled.