1. Lyrics are not searchable in iTunes. Remember a few words from a song but not the song name, album, or artist? Good luck locating it!
2. Song lyrics are only displayed in the Info pane. Why not in the visualization mode?
3. Song lyrics cannot be simultaneously added to multiple recordings of the same song.
4. The “Reveal In Library” arrow widgets’ Option-modified behavior doesn’t work anymore. Update: the Option-modifed behavior works if you revert defaults write com.apple.iTunes invertStoreLinks to the normal setting, then switch it back.
5. It is no longer possible to search by Composer. Commenter Sven S. Porst informed me that the Composer (and Song) search filters become available when the “Music” group is selected. Mea culpa. Perhaps I should re-title this post “iTunes 5 Lyrics: Nearly Useless”.

The new paint job is nice (still visually distinctive in Exposé, though not as heavy as the metal), but I’m not impressed thus far. With regard to lyrics, the lesson is: if you are going to implement a feature, do it right or don’t do it at all.