The existing search for Pier 1 and Smallwiki only allowed simple text searches. Also, for a large wiki, the Ajax search becomes very unresponsive. One of the changes in Pier-SW2-SW1Features was to cause the search to originate from the present page, not from the root, so all searching is faster.
The Advanced Search that was added in SW1 and Pier used light-box and was unwieldy. It is no longer present for Pier 2 & 3 - the existing search works quite well.