For my part, my surprise comes from the fact that I have to use the free-text search UI to list matches for a tag, and whether it matches free text or a tag is completely opaque. It is hostile UI when I can filter on "Games" in the category list, and search for "Angry Birds" by free text, and yet tags live in a nebulous nowhere-space. If I wanted to find apps titled "<Language> Essentials", I'd be pretty annoyed to find them disappear behind an unexpected magic keyword-to-tag search.

In this case, there is no good place to put tag search because tags aren't first-class citizens.