Why not E major?

Why have I never taught the E major P&F from WTCI?   What a gorgeous, light piece.  After playing it through today I am determined to get one of my students to learn it.  Only four pages for both pieces, only three voices in the fugue, no other elimination factors like long trills.  Just beautiful, sunlit simplicity.  This 9th P&F was played indeed on July 9, but somehow the day slipped into July 10 before writing this, just after midnight.