As you know, we're constantly working on refining and improving WikiTree. Maybe tracing out the development of these search features will help:
We started with a very basic text search engine. You enter keywords you get results. The current state of it is at http://www.wikitree.com/wiki/Special:SearchPerson
We later developed a feature we called "FindMatches." Instead of entering a name and browsing results, it will automatically do searches for *all* the names in your Watchlist. You can browse the results one at a time. If there are no matches for a name none are shown. It's a handy tool.
We added a feature to FindMatches where you could just search for one name. In many ways this is what you would get at Special:SearchPerson but it has the FindMatches options.
To make things convenient, we added a one-click no-options FindMatches search that has a single name filled in. That's what you get when you click the magnifying glass.
Since a lot of people use that one-click search, I know we need to now go back and add options to it.
However, we were working on MatchBot and now we're working on pre-matching for gedcoms, prior to import. When these are done (and other priorities) are worked through, we'll go back to improving the one-name search.