I agree. When looking at the three albums as a set, they make perfect sense. I also agree about Bedtime Stories and MDNA being transitions. Grouping Erotica, BS, and Ray of Light as a set also makes sense, because you have the hard, sexual R&B of Erotica giving way to the soft, tamer Bedtime Stories with hints of techno and trance (the title track), ending with Ray of Light's techno, dream-pop. If we look at MDNA as a transition between Hard Candy and 13, that means 13 could lend itself to hard some EDM leanings, stripped of MDNA's R&B, urban vibe. It's an interesting theory to think about.