+1 Hardness does not really drive the tone differences among these three general board materials. Again, Morado (also known as Pau Ferro) really does a nice job of a 'RW' look with a tone that has a bit more of those quick upper mids, more similar to maple to me versus RW.
Another thing that I learned from TB is that (if I remember this correctly) maple boards typically have a finish on them, whereas RW and ebony do not. I assume this also impacts the tone and feel a bit, and blurs the relationship between tone and hardness even more.
+1 to Ken's +1 on the maple finish. Gloss maple boards have much different vibe. I would say an unfinished board is very close to pau ferro/morado but a thick glossy finish on the maple scoops out the sound (to my ear).