Each scheme has a personality that was greatly imbued by the seres/movie. When you get the Skull Leader, what you are really buying is a Roy Focker action figure. You see his personality in the toy itself. You may also get the same character in different points of the series or movie. That's why people are buying the Hikaru 1S even thought they already have the 1A, and why people are crying out for the Max 1S. Unfortunately they haven't released one of my favorite characters/valks, which is the Max TV 1A which along with the Hikaru 1J represents the highpoint of the series for me. That's when Roy ruled the sky and vermillion team was still a whole (I'm not holding my breath for a Kakizake 1A). Another thing that's a dream for me would be a TV style Quadrono armor.
I don't know if any of you guys collected He-Man and the MAsters Of the Universe action figures in the 80's. But it was almost the same thing. There were two sets of bodies at first and each one just had a different head and different armor, yet we were compelled to collect each one. Later on they added more variety but they were still essentialy the same.