Awesome Gustavo, yes you broke it out perfectly! The big plus with this multi-node approach is that you can do stuff I haven't implemented, like rotate the texture, or more easily mix several matcaps together, add bump etc (though I guess you could do that with the single shader, too.)
The shader I made is the bare bones, I strongly urge anyone interested to dive in. I'd love it if someone better at this kind of thing blew my little shader out of the water with something more robust. If we can get a really strong solution it will be a major boon, just look at the mileage Zbrush users get out of matcap shading - it's a very robust way to shade, in particular for modeling/sculpting and for stills.
