Now that I've watched it twenty or so times, I think it deserves to be reappraised.
It's a surprisingly subtle piece. It's minimalist nature encourages us the viewer to consider how we feel about the 50th and reflect upon our own memories. The simplistic nature of the font, it's geometry and composition invites us to remember the many titles and logos that have adorned the show since it began, our entry point to the adventure that follows.
It's very simplicity makes the whole approach more intimate and personal. The sparse voiceover does nothing to disturb our enjoyment, but invites us to participate and share our thoughts. It's no longer just the 50th anniversary of the show, it's the 50th anniversary of us watching the show.
It is a masterpiece.